Security context handling in 5G during handover

ABSTRACT

The present disclosure relates to methods and apparatus for flexible, security context management during AMF changes. One aspect of the disclosure is a mechanism for achieving backward security during AMF changes. Instead of passing the current NAS key to the target AMF, the source AMF derives a new NAS key, provides the new NAS key to the target AMF, and sends a key change indication to the UE, either directly or through some other network node. The UE can then derive the new NAS key from the old NAS key. In some embodiments, the AMF may provide a key generation parameter to the UE to use in deriving the new NAS key. In other embodiments, the target AMF may change one or more security algorithms.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/714,494, filed 13 Dec. 2019, which is a continuation of U.S. patentapplication Ser. No. 16/235,632 filed 28 Dec. 2018 and granted as U.S.Pat. No. 10,542,428 on 21 Jan. 2020, which is a continuation ofPCT/EP2018/081943, filed 20 Nov. 2018, which in turn claims priority toU.S. Provisional Application No. 62/588,856, filed 20 Nov. 2017. Thedisclosures of each of these references are incorporated in theirentireties by reference herein.

TECHNICAL FIELD

The present disclosure relates generally to security in wirelesscommunication networks and, more particularly, to methods and apparatusfor security context handling during a handover of a user equipment.

BACKGROUND

The Third Generation Partnership Project (3GPP) is currently developingthe standards for Fifth Generation (5G) systems. It is expected that 5Gnetworks will support many new scenarios and use cases and will be anenabler for the Internet of Things (IoT). It is also expected that 5Gsystems will provide connectivity for a wide range of new devices suchas sensors, smart wearables, vehicles, machines, etc. Flexibility willbe a key property in 5G systems. This new flexibility is reflected inthe security requirements for network access that mandate the support ofalternative authentication methods and different types of credentialsother than the usual Authentication and Key Agreement (AKA) credentialspre-provisioned by the operator and securely stored in the UniversalIntegrated Circuit Card (UICC). More flexible security features wouldallow factory owners or enterprises to leverage their own identity andcredential management systems for authentication and access networksecurity.

Among the new security features in 5G systems is the introduction of aSecurity Anchor Function (SEAF). The purpose of the SEAF is to cater tothe flexibility and dynamicity in the deployment of the 5G core networkfunctions, by providing an anchor in a secure location for key storage.In fact, the SEAF is expected to leverage virtualization to achieve thedesired flexibility. As a consequence, the Access and MobilityManagement Function (AMF), the 5G function responsible for access andmobility management, can be deployed in a domain that is potentiallyless secure than the operator's core network, while the master keyremains in the SEAF in a secure location.

The SEAF is intended to establish and share a key denoted Kseaf with theuser equipment (UE), that is used for deriving other keys, such as thekeys for the control plane protection (e.g., Kcn key) and the radiointerface protection. These keys generally correspond to the non-accessstratum (NAS) keys and the access stratum key (KENB) in Long TermEvolution (LTE) systems. The SEAF is assumed to reside in a securelocation and the Kseaf key would never leave the SEAF. The SEAFcommunicates with the AMFs and provision the necessary key material(derived from the Kseaf key) for the protection of the control plane(CP) and user plane (UP) traffic with the user equipment (UE). Oneadvantage of this approach is that it avoids re-authentication each timea UE moves from an area served by one AMF to an area served by anotherAMF. In fact, authentication is a costly procedure in particular whenthe UE is roaming.

Recently, a proposal has been introduced to co-locate the SEAF and AMF,which defeats the purpose of the SEAF in the first place. It is worthnoting that the security design in LTE systems was conceptually based onthe assumption that the mobility management entity (MME), i.e. the noderesponsible for mobility management in LTE systems, is always located ina secure location within the operator core network. This assumption doesnot apply to the AMF in 5G systems. In dense areas, an AMF could bedeployed closer to the edge of the network and thus potentially inexposed locations (e.g., in a shopping mall). Therefore, during an AMFchange, it is possible that one of the AMFs is not located in an equallysecure domain as the other, and therefore the target or the source AMFmight need to shield itself from the other.

The Evolved Packet System (EPS) relied on the assumption that the MME isalways located in a secure location. Therefore, during an MME change,the new MME simply fetched the security context of the UE from theprevious MME. In addition, an MME may optionally trigger a newauthentication for forward security.

With legacy mechanisms, forward security (i.e. the old MME does not knowthe security context used by the new MME) could be achieved viare-authentication but there was no mechanism for backward security (i.e.the new MME does not know the security context used by the old MME). Thenew AMF may trigger a new authentication thus eliminating anypossibility for the old AMF to determine the new keys. The need forre-authentication could, for example, be based on an operator policytaking into account the location of the different AMFs.

Relying solely on the authentication procedure is not very efficientsince, performance wise, it is one of the most costly procedures.Therefore, there remains a need to provide security when changing AMFswithout the need for re-authentication.

SUMMARY

The present disclosure relates to methods and apparatus for flexible,security context management during AMF changes. One aspect of thedisclosure is a mechanism for achieving backward security during AMFchanges. Instead of passing the current NAS key to the target AMF, thesource AMF derives a new NAS key, provides the new NAS key to the targetAMF, and sends a key change indication to the UE, either directly orthrough some other network node. The UE can then derive the new NAS keyfrom the old NAS key. In some embodiments, the source AMF may provide akey generation parameter to the UE to use in deriving the new NAS key.In other embodiments, the target AMF may change one or more securityalgorithms.

In another embodiment of the disclosure, a key change indication and/orkey derivation parameter used to drive the new NAS key is sent from thetarget AMF to the target base station in a handover request. In responseto the handover request, the target base station generates a handovercommand and sends the handover command to the target AMF. The handovercommand includes the key change indication and/or key derivationparameter. The target AMF generates and sends a transparent container tothe source base station including the handover command. The transparentcontainer is forwarded by the source AMF and source base station all theway down to the UE.

Other aspects and embodiments of the disclosure are included in theenumerated embodiments.

One aspect of the disclosure comprises a method implemented by a sourcebase station in a wireless communication network for transferring asecurity context during a handover of a user equipment. The methodcomprises sending a first handover message to a source mobilitymanagement function in a core network of the wireless communicationnetwork to initiate a handover of a user equipment; receiving,responsive to the first handover message, a second handover message fromthe source mobility management function, the second handover messageincluding a transparent container; forwarding the transparent containerto the user equipment; receiving a key change indication indicating thata non-access stratum key has been changed; and forwarding the key changeindication to the user equipment.

Another aspect of the disclosure comprises a source base stationconfigured to perform the method of the preceding paragraph.

Another aspect of the disclosure comprises a method implemented by oneor more core network nodes in a core network of a wireless communicationnetwork that provide a source mobility management function. The methodcomprises receiving, from a source base station in an access network ofthe wireless communication network, a first handover message indicatingthat a handover of a user equipment is needed; generating a newnon-access stratum key; sending, responsive to the handover message, thenew non-access stratum key to a target mobility management function inthe core network of the wireless communication network; receiving, fromthe target mobility management function, a transparent container; andsending the transparent container to the user equipment in a secondhandover message; and sending a key change indication to the userequipment, said key change indication indicating that the non-accessstratum key has been changed.

Another aspect of the disclosure comprises core network node configuredto perform the method of the preceding paragraph.

Another aspect of the disclosure comprises a method implemented by oneor more core network nodes in a core network of a wireless communicationnetwork that provide a target mobility management function. The methodcomprises receiving, from a source mobility management function in acore network, a new non-access stratum key; establishing a new securitycontext based on the new non-access stratum key; receive an informationblock from the target base station, said information block including akey change indication indicating that a non-access stratum key has beenchanged; and sending, to the source mobility management function, atransparent container including the key change indication received fromthe target base station.

Another aspect of the disclosure comprises core network node configuredto perform the method of the preceding paragraph.

Another aspect of the disclosure comprises a method implemented by atarget base station in a wireless communication network. The methodcomprises receiving, from a target mobility management function, ahandover request; generating, responsive to the handover request, aninformation block including a key change indication indicating that anon-access stratum key has been changed; and sending a transparentcontainer with the key change indication to the target mobilitymanagement function for forwarding to the user equipment.

Another aspect of the disclosure comprises a target base stationconfigured to perform the method of the preceding paragraph.

Another aspect of the disclosure comprises a method implemented by auser equipment in a wireless communication network. The method comprisesreceiving a handover message from a source base station in firstmobility management domain of the wireless communication network, saidhandover message including a transparent container and a key changeindication indicating that a non-access stratum key has been changed;performing a handover from the source base station to a target basestation in a second mobility management domain of the wirelesscommunication network; and establishing, responsive to the key changeindication, a new security context with a target mobility managementfunction, said new security context including a new non-access stratumkey.

Another aspect of the disclosure comprises a user equipment configuredto perform the method of the preceding paragraph.

Another aspect of the disclosure comprises a method implemented by auser equipment in a wireless communication network. The method comprisesreceiving a handover message from a source base station in firstmobility management domain of the wireless communication network, saidhandover message including a transparent container and a key changeindication indicating that a core network key has been changed;performing a handover from the source base station to a target basestation in a second mobility management domain of the wirelesscommunication network; and establishing, responsive to the key changeindication, a new security context with a target mobility managementfunction, said new security context including a new core network key.

Another aspect of the disclosure comprises a user equipment configuredto perform the method of the preceding paragraph.

Another aspect of the disclosure comprises a method implemented by oneor more core network nodes in a core network of a wireless communicationnetwork that provide a target mobility management function. The methodcomprises receiving, from a source mobility management function in acore network, a new core network key; establishing a new securitycontext based on the new core network key; receive an information blockfrom the target base station, said information block including a keychange indication indicating that a new core network key has beenchanged; and sending, to the source mobility management function, atransparent container including the key change indication received fromthe target base station.

Another aspect of the disclosure comprises core network node configuredto perform the method of the preceding paragraph.

Another aspect of the disclosure comprises computer programs toimplement the methods described in the preceding paragraphs.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an exemplary wireless communication network.

FIG. 2 illustrates a procedure for security context handling during ahandover.

FIG. 3 illustrates a first exemplary key generation procedure.

FIG. 4 illustrates a second exemplary key generation procedure

FIG. 5 illustrates second procedure for security context handling duringa handover.

FIG. 6 illustrates a third procedure for security context handlingduring a handover.

FIG. 7 illustrates a fourth procedure for security context handlingduring a handover.

FIG. 8 illustrates a fifth procedure for security context handlingduring a handover.

FIG. 9 illustrates a method implemented by a source base station duringa handover.

FIG. 10 illustrates a method implemented by a source AMF during ahandover.

FIG. 11 illustrates a method implemented by a target AMF during ahandover.

FIG. 12 illustrates a method implemented by a UE during a handover.

FIG. 13 illustrates another method implemented by a source base stationduring a handover.

FIG. 14 illustrates another method implemented by a source AMF during ahandover.

FIG. 15 illustrates another method implemented by a target AMF during ahandover.

FIG. 16 illustrates a method implemented by a target base station duringa handover.

FIG. 17 illustrates a method implemented by a UE during a handover.

FIG. 18 illustrates an exemplary base station configured to implementthe security context handling procedures as herein described.

FIG. 19 illustrates an exemplary core network node configured toimplement the security context handling procedures as herein described.

FIG. 20 illustrates an exemplary user equipment configured to implementthe security context handling procedures as herein described.

FIG. 21 illustrates an exemplary wireless network according to anembodiment.

FIG. 22 illustrates an exemplary UE according to an embodiment.

FIG. 23 illustrates an exemplary virtualization environment according toan embodiment.

FIG. 24 illustrates an exemplary telecommunication network connected viaan intermediate network to a host computer according to an embodiment.

FIG. 25 illustrates an exemplary host computer communicating via a basestation with a user equipment over a partially wireless connectionaccording to an embodiment.

FIGS. 26-29 illustrate an exemplary methods implemented in acommunication system, according to an embodiment.

FIG. 30 illustrates a method implemented by a UE during a handover.

FIG. 31 illustrates another method implemented by a target AMF during ahandover.

DETAILED DESCRIPTION

Referring now to the drawings, an exemplary embodiment of the disclosurewill be described in the context of a 5G wireless communication network.Those skilled in the art will appreciate that the methods and apparatusherein described are not limited to use in 5G networks, but may also beused in wireless communication networks operating according to otherexisting and future standards.

FIG. 1 illustrates a wireless communication network 10 according to oneexemplary embodiment. The wireless communication network 10 comprises aradio access network (RAN) 20 and a core network 30. The RAN 20comprises one or more base stations 25 providing radio access to UEs 70operating within the wireless communication network 10. The basestations 25 are also referred to as gNodeBs (gNBs). The core network 30provides a connection between the RAN 20 and other packet data networks80.

In one exemplary embodiment, the core network 30 comprises anauthentication server function (AUSF) 35, access and mobility managementfunction (AMF) 40, session management function (SMF) 45, policy controlfunction (PSC) 50, unified data management (UDM) function 55, and userplane function (UPF) 60. These components of the wireless communicationnetwork 10 comprise logical entities that reside in one or more corenetwork nodes. The functions of the logical entities may be implementedby one or more processors, hardware, firmware, or a combination thereof.The functions may reside in a single core network node, or may bedistributed among two or more core network nodes.

The AMF 40, among other things, performs mobility management functionssimilar to the MME in LTE. The AMF and MME are referred to hereingenerically as mobility management functions. In the exemplaryembodiment shown in FIG. 1, the AMF 40 is the termination point fornon-access stratum (NAS) security. The AMF 40 shares a key, denoted thecore network key (Kcn), with the UE 70 that is used to derive the NASlower level protocol keys for integrity and confidentiality protection.The Kcn is generally equivalent to the Kasme in the Evolved PacketSystem (EPS), or the KAMF key. It is always the case that followingauthentication, a new Kcn is taken into use. How the Kcn key isestablished after authentication is not a material aspect of the presentdisclosure. The methods and apparatus described herein do not depend onthe particular method used for computing Kcn after authentication. Thatis, the security context handling methods work regardless of whether theKcn is derived from a higher level key or is established directly by theauthentication procedure similar to the establishment of Kasme in EPS.In an embodiment, the security context is a 5G Security Context, whichcomprises a 5G NAS Security Context and an 5G AS Security context. Inanother embodiment, the security context is the 5G NAS SecurityContext.5G NAS security context consists in one embodiment of KAMF, akey set identifier associated with the KAMF, UE security capabilities(???), and an uplink NAS COUNT value and a downlink NAS COUNT value.Once a UE 70 is authenticated, the UE 70 may move between cells withinthe network. When a UE 70 moves between cells while in a connected mode,a handover is executed. When a UE 70 in idle mode moves between cells, alocation update procedure may be executed. The AMF 40 keeps track of thelocation of the UE 70 in its domain. Typically, the core network 30 willhave multiple AMFs 40, each providing mobility management services in arespective domain. When a UE 70 moves between cells supervised bydifferent AMFs 40, the security context needs to be transferred from thesource AMF 40 to the target AMF 40.

In LTE systems, the security context is transferred unaltered from asource mobility management entity (MME) to the target MME during aninter-MME handover or location update. Following an AMF change, a NASsecurity mode command (SMC) may be performed, which takes new NAS andaccess stratum (AS) keys into use. Generation of NAS and AS keys may benecessary, for example, when an algorithm change is needed at the NASlevel. Generally, changing the algorithm used at the NAS protocol layerdoes not have any effect on the AS keys. However, changing the main NAScontext key renders the current AS keys outdated.

One aspect of the disclosure is a mechanism for achieving backwardsecurity during AMF changes. Instead of passing the current NAS key tothe target AMF 40, the source AMF 40 derives a new NAS key, provides thenew NAS key to the target AMF 40, and sends a key change indication tothe UE 70. The UE 70 can then derive the new NAS key from the old NASkey. In some embodiments, the source AMF 40 may provide a key generationparameter to the UE 70 to use in deriving the new NAS key. In otherembodiments, the target AMF 40 may change one or more securityalgorithms.

FIG. 2 illustrates an exemplary procedure for transferring a securitycontext during a handover where the AMF changes. The procedure shown inFIG. 2 is based on the S-1 handover procedure from 3GPP specification TS23.401, § 5.5.1.2.2 with modifications to handle a change in the NASkey. At step 1, the source base station 25 (e.g., source gNB) decides toinitiate an N2-based handover due, for example, to no Xn connectivity tothe target base station 25 (e.g. target gNB). The Xn interface is the 5Gequivalent of the X2 interface in EPS. At step 2, the source basestation 25 sends a handover required message (or 5G equivalent ofhandover required message) to the source AMF 40. This is the AMF 40currently serving the UE 70, with which it shares a full NAS securitycontext based on a Kcn key. The Kcn key was established possiblyfollowing a previous authentication or AMF 40 change procedure. At step3, the source AMF 40 selects the target AMF 40 and decides to derive anew Kcn key in order to shield itself and all the previous sessions fromthe target AMF 40. The decision to derive a new key may be based onoperator specific security policy. At step 4, the source AMF 40 sends aforward relocation request message (or 5G equivalent) including the newKcn key along with any relevant security parameters, such as the UEcapabilities. The target AMF 40 uses this Kcn key to set up a newsecurity context and derive a new AS key.

At step 5, the target AMF 40 sends a handover request (or 5G equivalent)to the target base station 25. The handover request includes the new ASkey and all relevant security parameters, such as the UE capabilities.This establishes the UE 70 security context at the target base station25. At step 6, the target base station 25 acknowledges the handoverrequest. Responsive to the acknowledgement, the target AMF 40 sends, atstep 7, a forward relocation response message (or 5G equivalent)including a target to source transparent container to the source AMF 40.This container is forwarded all the way down to the UE 70 in steps 8 and9.

At steps 8 and 9, the source AMF 40 sends a handover command message tothe UE 70 via the source base station 25, which forwards the handovercommand to the UE 70. The handover command message from the source AMF40 to the source base station 25 includes the relevant information fromthe forward relocation response message (e.g. target to sourcetransparent container, bearers subject of forwarding, bearers torelease, etc.) and a key change indication indicating that a new Kcn hasbeen derived. The key change indication may comprise an explicit keychange indicator flag set to a value indicating that the Kcn key hasbeen changed. Responsive to the key change indication, the UE 70establishes a new security context and derives a new Kcn. The UE 70 usesthe new Kcn key to derive a new AS key for communicating with the targetbase station 25.

FIG. 3 illustrates a first key derivation procedure. In this embodiment,it is assumed that the key derivation function (KDF) derives the new Kcnkey based solely on the old Kcn key. This key chaining from AMF 40 toAMF 40 may continue on until a new authentication is performed. It maybe left to the operator's policy how to configure the AMF 40 in respectto which security mechanism is selected during an AMF 40 change. Forexample, depending on an operator's security requirements, the operatorcan decide whether to perform re-authentication at the target AMF 40, orwhether a key change is needed at the source AMF 40.

FIG. 4 illustrates another key derivation procedure. This embodiment maybe useful in scenarios where an AMF 40 needs to prepare keys in advancefor more than one potential target AMF 40. In this case, an additionalkey derivation parameter is needed for cryptographic separation, so thatdifferent Kcn keys are prepared for different potential target AMFs.Depending on the parameter type, the UE 70 might need to be providedwith the chosen key derivation parameter in addition to the key changeindication. In some embodiments, the key derivation parameter my alsoserve as an implicit key change indication so that a separate key changeindication is not required. For example, where the key derivationparameter comprises a nonce generated by the source AMF 40, the nonceneeds to be provided to the UE 70. Other potential key derivationparameters include a timestamp, a version number, and a freshnessparameter. However, in scenarios where the key change parameter isotherwise available to the UE 70, such as an AMF 40 publicidentifier-like parameter, it may not be necessary to provide the UE 70with the key derivation parameter.

FIG. 5 illustrates a handover procedure where a freshness parameter orother key derivation parameter is used to derive the new Kcn key. Thisprocedure is generally the same as the procedure shown in FIG. 2. Forthe sake of brevity, steps that are unchanged are not described. At step3, the source AMF 40 selects the target AMF 40 and decides to derive anew Kcn key in order to shield itself and all the previous sessions fromthe target AMF 40. In this embodiment, the source AMF 40 generates afreshness parameter (e.g., version number) and uses the freshnessparameter to derive the new Kcn key. At step 4, the source AMF 40 sendsa forward relocation request message (or 5G equivalent) including thenew Kcn key along with any relevant security parameters, such as the UEcapabilities. The target AMF 40 uses this Kcn key to set up a newsecurity context and derive a new AS key. The source AMF 40 does notprovide the freshness parameter to the new AMF 40. Instead, at step 8,the source AMF 40 sends a handover command to the source base station25, wherein the handover command includes the freshness parameter inaddition to or in place of the key change indication. As noted above,the freshness parameter may serve as an implicit key change indication.Responsive to the key change indication and/or freshness parameter, theUE 70 establishes a new security context and derives a new Kcn using thefreshness parameter. The UE 70 may use the new Kcn key to derive a newAS key for communicating with the target base station 25.

In LTE systems, a NAS algorithm change at the target AMF 40 can onlytake effect through a NAS SMC procedure. Since the UE 70 capabilitiesare sent with other UE 70 context information to the target AMF 40, itis possible for the target AMF 40 to indicate which new NAS algorithmshave been selected. FIG. 6 illustrates an exemplary handover procedurewhere the target AMF 40 selects one or more new NAS security algorithms(e.g., cryptographic algorithms). Steps 1-4 are the same as described inFIG. 2. At step 5, the target AMF 40 selects one or more new NASsecurity algorithms. Steps 6 and 7 are the same as steps 5 and 6 in FIG.2. At step 8, the target AMF 40 includes an indication of the newsecurity algorithms in the transparent container to the sourceinformation element of the forward relocation response message sent tothe source AMF 40. This container is forwarded all the way down to theUE 70 in steps 9 and 10. The security algorithm indication may beincluded with the key change indication in the handover command, or in aseparate message. As a consequence, the UE 70 has all the necessaryparameters to activate the NAS security context with the target AMF 40without the need of a NAS SMC. This mechanism works regardless how theKcn key is derived.

FIG. 7 illustrates an exemplary handover procedure where the target basestation 25 generates a handover command, denoted HO-CMD, including thekey change indication and/or key derivation parameter. Steps 1-3 are thesame as described in FIG. 2. At step 4, the source AMF 40 sends aforward relocation request message (or 5G equivalent) including the newKCN key along with any relevant security parameters, such as the UEcapabilities, to the target AMF 40. In this embodiment, the source AMF40 also includes a freshness parameter or other key derivation parameterused to derive the new KCN key in the forward relocation request. Thetarget AMF 40 uses this KCN key to set up a new security context andderive a new AS key.

At step 5, the target AMF 40 sends a handover request (or 5G equivalent)to the target base station 25. The handover request includes a keychange indication, along with the freshness parameter received from thesource AMF 40 and all relevant security parameters, such as the new ASkey and the UE capabilities. As noted above, the key change indicationmay comprise an explicit key change indicator flag set to a valueindicating that the KCN key has been changed. The key derivationparameter may also serve as an implicit key change indication. Thisestablishes the UE 70 security context at the target base station 25.

At steps 6 and 7, the target base station 25 generates the handovercommand HO-CMD and sends the handover command HO-CMD to the target AMF40 in a handover request acknowledgement message. In one embodiment, thehandover command HO-CMD includes the key change indication and keyderivation parameter received from the target AMF 40. In otherembodiments, the key change indication and freshness parameter are sentseparately from the handover command HO-CMD, either as separateinformation elements in the handover request acknowledgement, or inseparate messages. In this case the key change indication and keyderivation parameter may be sent together. In one embodiment, thehandover command HO-CMD is transmitted to the target AMF in an RRCtransparent container or other information block. The RRC transparentcontainer or information block may also include the key changeindication and/or key derivation parameter (e.g. freshness parameter) ifnot already included in the handover command HO-CMD.

Responsive to the handover request acknowledgement, the target AMF 40sends, at step 8, a forward relocation response message (or 5Gequivalent) including a target to source transparent container to thesource AMF 40. The target to source transparent container includes thehandover command HO-CMD generated by the target base station 25. Thetarget to source transparent container may further include the keychange indication and/or freshness parameter, either as part of thehandover command HO-CMD, or as separate information elements. Thiscontainer is forwarded all the way down to the UE 70 in steps 9 and 10.

At steps 9 and 10 the source AMF 40 sends a handover command message tothe UE 70 via the source base station 25. It should be noted that thehandover command messages sent in steps 8 and 9 are different from thehandover command HO-CMD generated by the target base station 25, whichis included in the handover command messages sent at steps 8 and 9. Thehandover command message from the source AMF 40 to the source basestation 25 sent at step 8 includes the target to source transparentcontainer with the handover command HO-CMD from the target base station25. The source base station 25 constructs the handover command messagesent at step 10 using the target to source transparent container. In oneembodiment, the handover command message sent at step 10 from the sourcebase station 25 to the UE 70 includes the target to source transparentcontainer with the HO-CMD and possibly the key change indication and/orkey derivation parameter. Responsive to the key change indication, theUE 70 establishes a new security context and derives a new KCN. The UE70 uses the new KCN key to derive a new AS key for communicating withthe target base station 25.

In some embodiments of the disclosure, the freshness parameter can beomitted if the UE 70 is able to determine it through other means (e.g.,from data broadcast by the base station or from other data known to theUE).

FIG. 8 illustrates another handover procedure where the target basestation generates a handover command HO-CMD. Steps 1-3 are the same asdescribed in FIGS. 2 and 7. At step 4, the source AMF 40 sends a forwardrelocation request message (or 5G equivalent) including the new KCN keyalong with any relevant security parameters, such as the UEcapabilities, to the target AMF 40. In this embodiment, the source AMF40 does not include the freshness parameter or other key derivationparameter used to derive the new KCN key in the forward relocationrequest. The target AMF 40 uses this KCN key to set up a new securitycontext and derive a new AS key.

At step 5, the target AMF 40 sends a handover request (or 5G equivalent)to the target base station 25. The handover request includes the new ASkey and all relevant security parameters, such as the UE capabilities.This establishes the UE 70 security context at the target base station25. At steps 6 and 7, the target base station 25 generates the handovercommand HO-CMD and sends the handover command HO-CMD to the target AMF40 in a handover request acknowledgement message as previouslydescribed. Responsive to the handover request acknowledgement message,the target AMF 40 sends, at step 8, a forward relocation responsemessage (or 5G equivalent) including a target to source transparentcontainer to the source AMF 40. The target to source transparentcontainer includes the handover command HO-CMD generated by the targetbase station 25. This container is forwarded all the way down to the UE70 in steps 9 and 10.

At steps 9 and 10 the source AMF 40 sends a handover command message tothe UE 70 via the source base station 25. The handover command messagesent from the source AMF 40 to the source base station 25 includes thehandover command HO-CMD from the target base station 25 in the target tosource transparent container. The handover command message furtherincludes a key change indication, and the key derivation parameter (e.g.freshness parameter) used to derive the new KCN key. As noted above, thekey change indication may comprise an explicit key change indicator flagset to a value indicating that the KCN key has been changed. The sourcebase station 25 constructs the handover command message sent at step 10using the target to source transparent container. In one embodiment, thehandover command message sent at step 10 from the source base station 25to the UE 70 includes the target to source transparent container. Thekey derivation parameter may also serve as an implicit key changeindication. Responsive to the key change indication, the UE 70establishes a new security context and derives a new KCN. The UE 70 usesthe new KCN key to derive a new AS key for communicating with the targetbase station 25.

FIG. 9 illustrates an exemplary method 100 implemented during a handoverby a source base station 25 in an access network of a wirelesscommunication network 10. The source base station 25 sends a firsthandover message to a source AMF 40 in a core network 30 of the wirelesscommunication network 10 to initiate a handover of a UE 70 (block 105).Subsequently, the source base station 25 receives, responsive to thefirst handover message, a second handover message from the source AMF 40(block 110). The second handover message includes a key changeindication indicating that a non-access stratum key has been changed.The source base station 25 forwards the second handover message with thekey change indication to the UE 70 (block 115).

FIG. 10 illustrates an exemplary method 150 implemented during ahandover by a source AMF 40 in a core network 30 of a wirelesscommunication network 10. The source AMF 40 receives, from the sourcebase station 25, a first handover message indicating that a handover ofthe UE 70 is needed (block 155). The source AMF generates a newnon-access stratum key (block 160), and sends the new non-access stratumkey to a target AMF 40 in the core network 30 of the wirelesscommunication network 10 (block 165). The source AMF 40 also sends a keychange indication to the UE 70 in a second handover message (block 170).The key change indication indicates a change of the non-access stratumkey.

FIG. 11 illustrates an exemplary method 200 implemented during ahandover by a target AMF 40 in a core network 30 of a wirelesscommunication network 10. The target AMF 40 receives, from the sourceAMF 40, a new non-access stratum key (block 205). The target AMFestablishes a new security context including a new access stratum keyderived from the new non-access stratum key (block 210), and sends thenew access stratum key to a target base station 25 (block 215).

FIG. 12 illustrates an exemplary method 250 implemented by a UE 70 in awireless communication network 10 during a handover. The UE 70 receivesa handover message including a key change indication from a source basestation 25 in the domain of a source AMF 40 of the wirelesscommunication network 10 (block 255). The key change indicationindicates to the UE 70 that a non-access stratum key has been changed.The UE 70 performs a handover from the source base station 25 to atarget base station 25 in a domain of a target AMF 40 (block 260). TheUE 70 establishes, responsive to the key change indication, a newsecurity context with the target AMF 40 (block 265). The new securitycontext includes a new non-access stratum key. The UE 70 may optionallycommunicate with the target AMF 40 using the new non-access stratum key(block 270).

FIG. 13 illustrates an exemplary method 300 implemented during ahandover by a source base station 25 in an access network of a wirelesscommunication network 10. The source base station 25 sends a firsthandover message to a source AMF 40 in a core network 30 of the wirelesscommunication network 10 to initiate a handover of a UE 70 (block 305).Subsequently, the source base station 25 receives, responsive to thefirst handover message, a second handover message including atransparent container from the source AMF 40 (block 310). In oneembodiment, the transparent container includes a handover commandgenerated by a target base station. The source base station 25 forwardsthe transparent container to the UE 70 (block 315). The source basestation 25 also receives a key change indication indicating that anon-access stratum key has been changed (block 320) and forward the keychange indication to the user equipment (block 325). In one embodiment,the key change indication is received along with the handover command inthe transparent container. In other embodiments, the key changeindication is received along with the transparent container in thesecond handover message.

In some embodiments of the method 300, the key change indication isreceived from the source AMF in the transparent container and forwardedto the UE 70 in the transparent container.

In some embodiments of the method 300, the key change indicationcomprises a key change indicator flag set to a value indicating that thenon-access stratum key has been changed.

In some embodiments of the method 300, the key change indicationcomprises a security parameter implicitly indicating that the non-accessstratum key has been changed. The security parameter may comprises oneof a nonce, timestamp, and freshness parameter.

Some embodiments of the method 300 further comprise receiving, from thesource AMF 40, a key derivation parameter needed by the UE 70 togenerate a new non-access stratum key; and forwarding the key derivationparameter to the UE 70. The key derivation parameter may comprise one ofa nonce, timestamp, and freshness parameter. In some embodiments, thekey derivation parameter is received with the key change indication inthe transparent container and forwarded to the UE 70 in the transparentcontainer. In some embodiments, the key derivation parameter serves asan implicit key change indication.

Some embodiments of the method 300 further comprise receiving, from thesource AMF 40, a security algorithm parameter indicating at least onesecurity algorithm to be used by the UE 70; and forwarding the securityalgorithm parameter to the UE 70. In some embodiments, the securityalgorithm parameter is received in the second handover message.

In some embodiments of the method 300, the first handover messagecomprises a handover required message indicating a need for a handoverof the UE 70.

In some embodiments of the method 300, the second handover messagecomprises a handover command including the transparent container.

In some embodiments of the method 300, the non-access stratum keycomprises a core network key (KCN).

FIG. 14 illustrates an exemplary method 350 implemented during ahandover by a source AMF 40 in a core network 30 of a wirelesscommunication network 10. The source AMF 40 receives, from the sourcebase station 25, a first handover message indicating that a handover ofthe UE 70 is needed (block 355). The source AMF generates a newnon-access stratum key (block 360), and sends the new non-access stratumkey to a target AMF 40 in the core network 30 of the wirelesscommunication network 10 (block 365). The source AMF 40 receives, fromthe target AMF 40, a transparent container (block 370). In oneembodiment, the transparent container includes a handover commandgenerated by a target base station. The source AMF 40 sends thetransparent container to the UE 70 in a second handover message (block375). The source AMF 40 also sends a key change indication to the UE 70(block 380). The key change indication indicates a change of thenon-access stratum key. In one embodiment, the key change indication issent along with the transparent container in the second handovermessage. In other embodiments, the key change indication is sent alongwith the handover command in the transparent container.

Some embodiments of the method 350 further comprise receiving the keychange from the target AMF 40 in the transparent container; andforwarding the transparent container with the key change indication tothe UE 70.

In some embodiments of the method 350, the key change indicationcomprises a key change indicator flag set to a value indicating that thenon-access stratum key has been changed.

In some embodiments of the method 350, the key change indicationcomprises a security parameter implicitly indicating that the non-accessstratum key has been changed. The security parameter may comprise one ofa nonce, timestamp, and freshness parameter.

Some embodiments of the method 350 further comprise sending, to thetarget AMF 40, a key derivation parameter used to derive the non-accessstratum key. The key derivation parameter may comprise one of a nonce,timestamp, and freshness parameter.

Some embodiments of the method 350 further comprise sending the keyderivation parameter to the UE 70.

Some embodiments of the method 350 further comprise receiving the keyderivation parameter from the AMF 40 in the transparent container; andsending the key derivation parameter to the UE 70 in the transparentcontainer.

In some embodiments of the method 350, generating the new non-accessstratum key comprises generating the new non-access stratum key from aprevious non-access stratum key.

In some embodiments of the method 350, generating the new non-accessstratum key comprises generating a key derivation parameter; andgenerating the new non-access stratum key from a previous non-accessstratum key and the key derivation parameter.

Some embodiments of the method 350 further comprise selecting the targetAMF 40; and wherein generating a new non-access stratum key is performeddepending on the selection of the target AMF 40.

In some embodiments of the method 350, generating the new non-accessstratum key comprises generating two or more non-access stratum keys,each for different target AMF 40s. The two or more non-access stratumkeys can be generated using different key derivation parameters.

Some embodiments of the method 350 further comprise sending one or moresecurity parameters to the target AMF 40. The one or more securityparameters may, in some instances, include UE 70 capability information.In some embodiments, the non-access stratum key and the one or moresecurity parameters are transmitted to the target AMF 40 in a forwardrelocation message.

Some embodiments of the method 350 further comprise receiving, from thetarget AMF 40, a security algorithm parameter indicating at least onesecurity algorithm; and forwarding the security algorithm parameter tothe UE 70. The security algorithm parameter may be received from thetarget AMF 40 in a forward relocation response message. Some embodimentsof the method 350 further comprise forwarding the security algorithmparameter to the UE 70 in the second handover message.

In some embodiments of the method 350, the first handover messagecomprises a handover required message indicating a need for a handoverof the UE 70.

In some embodiments of the method 350, the new non-access stratum key issent to the target AMF 40 in a forward relocation request message.

In some embodiments of the method 350, the non-access stratum keycomprises a core network key (KCN).

FIG. 15 illustrates an exemplary method 400 implemented during ahandover by a target AMF 40 in a core network 30 of a wirelesscommunication network 10. The target AMF 40 receives, from the sourceAMF 40, a new non-access stratum key (block 405). The target AMFestablishes a new security context based on the new non-access stratumkey (block 410). The new security context may include a new accessstratum key derived from the new non-access stratum key. Where a newaccess stratum key is derived, the target AMF 40 optionally sends thenew access stratum key to a target base station 25 (block 415). In oneembodiment, the new access stratum key is sent in a handover requestmessage. The target AMF also receives an information block including akey change indication from the target base station 25 (block 420). Theinformation block may be sent, for example, in an RRC transparentcontainer. In one embodiment, the information block further includes ahandover command generated by the target base station 25 and/or afreshness parameter for deriving the new non-access stratum key. Thetarget AMF 40 sends, to the source AMF 40, a transparent containerincluding the handover command received from the target base station 25(block 425). In some embodiments, the handover command in thetransparent container includes a key change indication and/or keyderivation parameter. In some embodiments, the target AMF 40 furtherreceives a key change indication and/or key change derivation parameter(e.g., freshness parameter) from the target base station 25 and forwardsthe key derivation parameter to the source AMF in the transparentcontainer along with the handover command.

Some embodiments of the method 400 further comprise receiving one ormore security parameters from the source AMF 40. The one or moresecurity parameters may include UE 70 capability information. In someembodiments, the security parameters is received with the new non-accessstratum key.

In some embodiments of the method 400, establishing the new securitycontext comprises selecting one or more security algorithms. Thesecurity algorithms may be selected based on the UE 70 capabilityinformation.

Some embodiments of the method 400 further comprise sending to thesource AMF 40, a security algorithm parameter indicating at least onesecurity algorithm for the new security context. The security algorithmparameter may be sent to the source AMF 40 in a forward relocationresponse message.

In some embodiments of the method 400, the new non-access stratum key isreceived from the source AMF 40 in a forward relocation request message.

In some embodiments of the method 400, the new access stratum key issent to the target base station 25 in a handover request.

In some embodiments of the method 400, the non-access stratum keycomprises a core network key (Kcn).

Some embodiments of the method 400 further comprise receiving the keychange indication from the target base station 25 in the transparentcontainer; and sending the key change indication to the source targetAMF 40 in the transparent container.

In some embodiments of the method 400, the key change indicationcomprises a key change indicator flag set to a value indicating that thenon-access stratum key has been changed.

In some embodiments of the method 400, the key change indicationcomprises a security parameter implicitly indicating that the non-accessstratum key has been changed. The security parameter may comprise one ofa nonce, timestamp, and freshness parameter.

Some embodiments of the method 400 sending, to the target base station25, a key derivation parameter used to derive the non-access stratumkey. In some embodiments, the key derivation parameter is received fromthe target base station 25 in the transparent container. The keyderivation parameter may comprises one of a nonce, timestamp, andfreshness parameter.

FIG. 16 illustrates an exemplary method 450 implemented during ahandover by a target base station 25 a wireless communication network10. The target base station 25 receives, from a target AMF 40, ahandover request indicating a need for a handover (block 455).Responsive to the handover request, the target base station 25 generatesan information block including a key change indication indicating that aNAS key has been changed (block 460). The information block, in oneexample, comprises an RRC transparent container. The key changeindication indicates that a NAS key has been changed. The target basestation 25 sends the information block with the key change indication toa target AMF 40 for forwarding to the UE 70 (block 465). In someembodiments, the information block may further comprise a handovercommand generated by the target base station and/or a key derivationparameter used to derive the new NAS key.

Some embodiments of the method 450 further comprise receiving the keychange indication from the target AMF 40 in the handover request.

In some embodiments of the method 450, the key change indicationcomprises a key change indicator flag set to a value indicating that thenon-access stratum key has been changed. In other embodiments,

In some embodiments of the method 450, the key change indicationcomprises a security parameter implicitly indicating that the non-accessstratum key has been changed. The security parameter may comprise one ofa nonce, timestamp, and freshness parameter.

Some embodiments of the method 450 further comprise receiving a keyderivation parameter used to drive the new non-access stratum key fromthe target AMF 40 in the handover request, and sending the keyderivation parameter to the target AMF 40 in the information block. Thekey derivation parameter may comprise one of a nonce, timestamp, andfreshness parameter.

FIG. 17 illustrates an exemplary method 475 implemented by a UE 70 in awireless communication network 10 during a handover. The UE 70 receives,from a from a source base station 25 in the domain of a source AMF 40 ofthe wireless communication network 10, a handover message including atransparent container and key change indication (block 480). The keychange indication indicates to the UE 70 that a non-access stratum keyhas been changed. In some embodiments, the transparent container furtherincludes a handover command generated by a target base station 25 and/ora key derivation parameter (e.g., freshness parameter used to derive thenew NAS key. The UE 70 performs a handover from the source base station25 to a target base station 25 in a domain of a target AMF 40 (block485). The UE 70 establishes, responsive to the key change indication, anew security context with the target AMF 40 (block 490). The newsecurity context includes a new non-access stratum key. The UE 70 mayoptionally communicate with the target AMF 40 using the new non-accessstratum key (block 495).

In some embodiments of the method 475, the key change indicationcomprises a key change indicator flag set to a value indicating that thenon-access stratum key has been changed.

In some embodiments of the method 475, the key change indicationcomprises a security parameter implicitly indicating that the non-accessstratum key has been changed. The security parameter may comprise one ofa nonce, timestamp, and freshness parameter.

Some embodiments of the method 475 further comprise receiving the keychange indication in the transparent container.

Some embodiments of the method 475 further comprise receiving a keyderivation parameter from the source base station 25, and generating thenew non-access stratum key using the key derivation parameter. The keyderivation parameter may comprise one of a nonce, timestamp, andfreshness parameter. In some embodiments, the key derivation parameteris received with the key change indication in the transparent container.In some embodiments, the key derivation parameter serves as an implicitkey change indication.

Some embodiments of the method 475 further comprise generating a newaccess stratum key from the new non-access stratum key, andcommunicating with a target base station 25 using the new access stratumkey.

Some embodiments of the method 475 further comprise receiving a securityalgorithm parameter from the source base station 25 identifying one ormore security algorithms used in the new security context. The securityalgorithm parameter may be received in the handover message along withthe key change indication.

In some embodiments of the method 475, the non-access stratum keycomprises a core network key (Kcn).

FIG. 18 illustrates the main functional components of base station 500configured to implement the security context handling methods as hereindescribed. The base station 500 comprises a processing circuit 510, amemory 530, and an interface circuit 540.

The interface circuit 540 includes a radio frequency (RF) interfacecircuit 545 coupled to one or more antennas 550. The RF interfacecircuit 540 comprises the radio frequency (RF) components needed forcommunicating with the UEs 70 over a wireless communication channel.Typically, the RF components include a transmitter and receiver adaptedfor communications according to the 5G standards or other Radio AccessTechnology (RAT). The interface circuit 540 further includes a networkinterface circuit 555 for communicating with core network nodes in thewireless communication network 10.

The processing circuit 510 processes the signals transmitted to orreceived by the base station 500. Such processing includes coding andmodulation of transmitted signals, and the demodulation and decoding ofreceived signals. The processing circuit 510 may comprise one or moremicroprocessors, hardware, firmware, or a combination thereof. Theprocessing circuit 510 includes a mobility unit 515 for performinghandover-related functions. The mobility unit 515 comprises theprocessing circuitry dedicated to mobility-related functions. Themobility unit 515 is configured to perform any of the methods andprocedures as herein described, including the methods shown in FIGS. 2,5-9, 13 and 16.

Memory 530 comprises both volatile and non-volatile memory for storingcomputer program code and data needed by the processing circuit 510 foroperation. Memory 530 may comprise any tangible, non-transitorycomputer-readable storage medium for storing data including electronic,magnetic, optical, electromagnetic, or semiconductor data storage.Memory 530 stores a computer program 535 comprising executableinstructions that configure the processing circuit 510 to implement themethods and procedures described herein including method 100 accordingto FIGS. 2 and 6-8. In general, computer program instructions andconfiguration information are stored in a non-volatile memory, such as aread only memory (ROM), erasable programmable read only memory (EPROM)or flash memory. Temporary data generated during operation may be storedin a volatile memory, such as a random access memory (RAM). In someembodiments, computer program 535 for configuring the processing circuit510 as herein described may be stored in a removable memory, such as aportable compact disc, portable digital video disc, or other removablemedia. The computer program 535 may also be embodied in a carrier suchas an electronic signal, optical signal, radio signal, or computerreadable storage medium.

FIG. 19 illustrates the main functional components of a core networknode 600 in the wireless communication network 10 configured toimplement the security context handling procedure as herein described.The core network node 600 may be used to implement core networkfunctions, such as the source AMF 40 and target AMF 40 as hereindescribed. Those skilled in the art will appreciate that a core networkfunction, such as the AMF 40, may be implemented by a single corenetwork node, or may be distributed among two or more core networknodes.

The core network node 600 comprises a processing circuit 610, a memory630, and an interface circuit 640. The interface circuit 640 includes anetwork interface circuit 645 to enable communication with other corenetwork nodes and with base stations 25 in the RAN.

The processing circuit 610 controls the operation of the core networknode 600. The processing circuit 610 may comprise one or moremicroprocessors, hardware, firmware, or a combination thereof. Theprocessing circuit 610 may include a NAS security unit 615 to handleNAS-related security functions and a mobility management unit 620 tohandle AMF 40s. Generally, the NAS security unit 615 is responsible forderiving security keys, establishing a security context, and otherrelated security functions. The mobility management unit 620 isresponsible for handling AMF 40s and related signalling. As describedpreviously, the NAS security unit 615 may provide the mobilitymanagement 620 unit with information, such as NAS keys, key derivationparameters, and other security parameters to be sent to the UE 70. Insome embodiments, the NAS security unit 615 and the mobility managementunit 620 may reside in the same core network node. In other embodiments,they may reside in different core network nodes. The NAS security unit615 and the mobility management unit 620 can be configured to performany of the methods and procedures as herein described, including themethods shown in FIGS. 2, 5-8, 10, 11, 14 and 15.

Memory 630 comprises both volatile and non-volatile memory for storingcomputer program code and data needed by the processing circuit 610 foroperation. Memory 630 may comprise any tangible, non-transitorycomputer-readable storage medium for storing data including electronic,magnetic, optical, electromagnetic, or semiconductor data storage.Memory 630 stores a computer program 635 comprising executableinstructions that configure the processing circuit 610 to implement themethods and procedures described herein including methods according toFIGS. 2-14. In general, computer program instructions and configurationinformation are stored in a non-volatile memory, such as a read onlymemory (ROM), erasable programmable read only memory (EPROM) or flashmemory. Temporary data generated during operation may be stored in avolatile memory, such as a random access memory (RAM). In someembodiments, a computer program 635 for configuring the processingcircuit 610 as herein described may be stored in a removable memory,such as a portable compact disc, portable digital video disc, or otherremovable media. The computer program 635 may also be embodied in acarrier such as an electronic signal, optical signal, radio signal, orcomputer readable storage medium.

FIG. 20 illustrates the main functional components of UE 700 configuredto implement the security context handling methods as herein described.The UE 700 comprises a processing circuit 710, a memory 730, and aninterface circuit 740.

The interface circuit 740 includes a radio frequency (RF) interfacecircuit 745 coupled to one or more antennas 750. The RF interfacecircuit 745 comprises the radio frequency (RF) components needed forcommunicating with the UEs 70 over a wireless communication channel.Typically, the RF components include a transmitter and receiver adaptedfor communications according to the 5G standards or other Radio AccessTechnology (RAT).

The processing circuit 710 processes the signals transmitted to orreceived by the UE 700. Such processing includes coding and modulationof transmitted signals, and the demodulation and decoding of receivedsignals. The processing circuit 710 may comprise one or moremicroprocessors, hardware, firmware, or a combination thereof. Theprocessing circuit 710 may include a NAS security unit 715 to handleNAS-related security functions and a mobility management unit 720 tohandle AMF 40s. Generally, the NAS security unit 715 is responsible forderiving security keys, establishing a security context, and othersecurity functions as herein described. The mobility management unit 720is responsible for handling AMF 40s and related signaling. In oneexemplary embodiment, the NAS security unit 715 and the mobilitymanagement unit 720 are configured to perform the methods and proceduresas herein described, including the methods shown in FIGS. 2, 5-8, 12 and17.

Memory 730 comprises both volatile and non-volatile memory for storingcomputer program code and data needed by the processing circuit 710 foroperation. Memory 730 may comprise any tangible, non-transitorycomputer-readable storage medium for storing data including electronic,magnetic, optical, electromagnetic, or semiconductor data storage.Memory 730 stores a computer program 735 comprising executableinstructions that configure the processing circuit 710 to implement themethods and procedures described herein including method 100 accordingto FIGS. 2 and 6-8. In general, computer program instructions andconfiguration information are stored in a non-volatile memory, such as aread only memory (ROM), erasable programmable read only memory (EPROM)or flash memory. Temporary data generated during operation may be storedin a volatile memory, such as a random access memory (RAM). In someembodiments, computer program 735 for configuring the processing circuit710 as herein described may be stored in a removable memory, such as aportable compact disc, portable digital video disc, or other removablemedia. The computer program 735 may also be embodied in a carrier suchas an electronic signal, optical signal, radio signal, or computerreadable storage medium.

FIG. 30 illustrates an exemplary method 875 implemented by a UE 70 in awireless communication network 10 during a handover. The UE 70 receives,from a source base station 25 in the domain of a source AMF 40 of thewireless communication network 10, a handover message including atransparent container and key change indication (block 880). The keychange indication indicates to the UE 70 that a core network key hasbeen changed. In some embodiments, the transparent container furtherincludes a handover command generated by a target base station 25 and/ora key derivation parameter (e.g., freshness parameter used to derive thenew core network key. The UE 70 performs a handover from the source basestation 25 to a target base station 25 in a domain of a target AMF 40(block 885). The UE 70 establishes, responsive to the key changeindication, a new security context with the target AMF 40 (block 890).The new security context includes a new core network key. The UE 70 mayoptionally communicate with the target AMF 40 using the new core networkkey (block 895).

In some embodiments of the method 875, the key change indicationcomprises a key change indicator flag set to a value indicating that thecore network key has been changed.

In some embodiments of the method 875, the key change indicationcomprises a security parameter implicitly indicating that the corenetwork key has been changed. The security parameter may comprise one ofa nonce, timestamp, and freshness parameter.

Some embodiments of the method 875 further comprise receiving the keychange indication in the transparent container.

Some embodiments of the method 875 further comprise receiving a keyderivation parameter from the source base station 25, and generating thenew core network key using the key derivation parameter. The keyderivation parameter may comprise one of a nonce, timestamp, andfreshness parameter. In some embodiments, the key derivation parameteris received with the key change indication in the transparent container.In some embodiments, the key derivation parameter serves as an implicitkey change indication.

Some embodiments of the method 875 further comprise generating a newaccess stratum key from the new core network key, and communicating witha target base station 25 using the new access stratum key.

Some embodiments of the method 875 further comprise receiving a securityalgorithm parameter from the source base station 25 identifying one ormore security algorithms used in the new security context. The securityalgorithm parameter may be received in the handover message along withthe key change indication.

FIG. 31 illustrates an exemplary method 800 implemented during ahandover by a target AMF 40 in a core network 30 of a wirelesscommunication network 10. The target AMF 40 receives, from the sourceAMF 40, a new core network key (block 805). The target AMF establishes anew security context with the new core network key (block 810). The newsecurity context may include a new access stratum key derived from thenew core network key. Where a new access stratum key is derived, thetarget AMF 40 optionally sends the new access stratum key to a targetbase station 25 (block 815). In one embodiment, the new access stratumkey is sent in a handover request message. The target AMF also receivesan information block including a key change indication from the targetbase station 25 (block 820). The information block may be sent, forexample, in an RRC transparent container. In one embodiment, theinformation block further includes a handover command generated by thetarget base station 25 and/or a freshness parameter for deriving the newcore network key. The target AMF 40 sends, to the source AMF 40, atransparent container including the handover command received from thetarget base station 25 (block 825). In some embodiments, the handovercommand in the transparent container includes a key change indicationand/or key derivation parameter. In some embodiments, the target AMF 40further receives a key change indication and/or key change derivationparameter (e.g., freshness parameter) from the target base station 25and forwards the key derivation parameter to the source AMF in thetransparent container along with the handover command.

Some embodiments of the method 800 further comprise receiving one ormore security parameters from the source AMF 40. The one or moresecurity parameters may include UE 70 capability information. In someembodiments, the security parameters is received with the new corenetwork key.

In some embodiments of the method 800, establishing the new securitycontext comprises selecting one or more security algorithms. Thesecurity algorithms may be selected based on the UE 70 capabilityinformation.

Some embodiments of the method 800 further comprise sending to thesource AMF 40, a security algorithm parameter indicating at least onesecurity algorithm for the new security context. The security algorithmparameter may be sent to the source AMF 40 in a forward relocationresponse message.

In some embodiments of the method 800, the new core network key isreceived from the source AMF 40 in a forward relocation request message.

In some embodiments of the method 800, the new access stratum key issent to the target base station 25 in a handover request.

Some embodiments of the method 800 further comprise receiving the keychange indication from the target base station 25 in the transparentcontainer; and sending the key change indication to the source targetAMF 40 in the transparent container.

In some embodiments of the method 800, the key change indicationcomprises a key change indicator flag set to a value indicating that thecore network key has been changed.

In some embodiments of the method 800, the key change indicationcomprises a security parameter implicitly indicating that the corenetwork key has been changed. The security parameter may comprise one ofa nonce, timestamp, and freshness parameter.

Some embodiments of the method 800 sending, to the target base station25, a key derivation parameter used to derive the core network key. Insome embodiments, the key derivation parameter is received from thetarget base station 25 in the transparent container. The key derivationparameter may comprise one of a nonce, timestamp, and freshnessparameter.

Additional Embodiments

Although the subject matter described herein may be implemented in anyappropriate type of system using any suitable components, theembodiments disclosed herein are described in relation to a wirelessnetwork, such as the example wireless network illustrated in FIG. 21.For simplicity, the wireless network of FIG. 21 only depicts network1106, network nodes 1160 and 1160 b, and WDs 1110, 1110 b, and 1110 c.In practice, a wireless network may further include any additionalelements suitable to support communication between wireless devices orbetween a wireless device and another communication device, such as alandline telephone, a service provider, or any other network node or enddevice. Of the illustrated components, network node 1160 and wirelessdevice (WD) 1110 are depicted with additional detail. The wirelessnetwork may provide communication and other types of services to one ormore wireless devices to facilitate the wireless devices' access toand/or use of the services provided by, or via, the wireless network.

The wireless network may comprise and/or interface with any type ofcommunication, telecommunication, data, cellular, and/or radio networkor other similar type of system. In some embodiments, the wirelessnetwork may be configured to operate according to specific standards orother types of predefined rules or procedures. Thus, particularembodiments of the wireless network may implement communicationstandards, such as Global System for Mobile Communications (GSM),Universal Mobile Telecommunications System (UMTS), Long Term Evolution(LTE), Narrowband Internet of Things (NB-IoT), and/or other suitable 2G,3G, 4G, or 5G standards; wireless local area network (WLAN) standards,such as the IEEE 802.11 standards; and/or any other appropriate wirelesscommunication standard, such as the Worldwide Interoperability forMicrowave Access (WiMax), Bluetooth, Z-Wave and/or ZigBee standards.

Network 1106 may comprise one or more backhaul networks, core networks,IP networks, public switched telephone networks (PSTNs), packet datanetworks, optical networks, wide-area networks (WANs), local areanetworks (LANs), wireless local area networks (WLANs), wired networks,wireless networks, metropolitan area networks, and other networks toenable communication between devices.

Network node 1160 and WD 1110 comprise various components described inmore detail below. These components work together in order to providenetwork node and/or wireless device functionality, such as providingwireless connections in a wireless network. In different embodiments,the wireless network may comprise any number of wired or wirelessnetworks, network nodes, base stations, controllers, wireless devices,relay stations, and/or any other components or systems that mayfacilitate or participate in the communication of data and/or signalswhether via wired or wireless connections.

As used herein, network node refers to equipment capable, configured,arranged and/or operable to communicate directly or indirectly with awireless device and/or with other network nodes or equipment in thewireless network to enable and/or provide wireless access to thewireless device and/or to perform other functions (e.g., administration)in the wireless network. Examples of network nodes include, but are notlimited to, access points (APs) (e.g., radio access points), basestations (BSs) (e.g., radio base stations, Node Bs, evolved Node Bs(eNBs) and NR NodeBs (gNBs)). Base stations may be categorized based onthe amount of coverage they provide (or, stated differently, theirtransmit power level) and may then also be referred to as femto basestations, pico base stations, micro base stations, or macro basestations. A base station may be a relay node or a relay donor nodecontrolling a relay. A network node may also include one or more (orall) parts of a distributed radio base station such as centralizeddigital units and/or remote radio units (RRUs), sometimes referred to asRemote Radio Heads (RRHs). Such remote radio units may or may not beintegrated with an antenna as an antenna integrated radio. Parts of adistributed radio base station may also be referred to as nodes in adistributed antenna system (DAS). Yet further examples of network nodesinclude multi-standard radio (MSR) equipment such as MSR BSs, networkcontrollers such as radio network controllers (RNCs) or base stationcontrollers (BSCs), base transceiver stations (BTSs), transmissionpoints, transmission nodes, multi-cell/multicast coordination entities(MCEs), core network nodes (e.g., MSCs, MMEs), O&M nodes, OSS nodes, SONnodes, positioning nodes (e.g., E-SMLCs), and/or MDTs. As anotherexample, a network node may be a virtual network node as described inmore detail below. More generally, however, network nodes may representany suitable device (or group of devices) capable, configured, arranged,and/or operable to enable and/or provide a wireless device with accessto the wireless network or to provide some service to a wireless devicethat has accessed the wireless network.

In FIG. 21, network node 1160 includes processing circuitry 1170, devicereadable medium 1180, interface 1190, auxiliary equipment 1184, powersource 1186, power circuitry 1187, and antenna 1162. Although networknode 1160 illustrated in the example wireless network of FIG. 21 mayrepresent a device that includes the illustrated combination of hardwarecomponents, other embodiments may comprise network nodes with differentcombinations of components. It is to be understood that a network nodecomprises any suitable combination of hardware and/or software needed toperform the tasks, features, functions and methods disclosed herein.Moreover, while the components of network node 1160 are depicted assingle boxes located within a larger box, or nested within multipleboxes, in practice, a network node may comprise multiple differentphysical components that make up a single illustrated component (e.g.,device readable medium 1180 may comprise multiple separate hard drivesas well as multiple RAM modules).

Similarly, network node 1160 may be composed of multiple physicallyseparate components (e.g., a NodeB component and a RNC component, or aBTS component and a BSC component, etc.), which may each have their ownrespective components. In certain scenarios in which network node 1160comprises multiple separate components (e.g., BTS and BSC components),one or more of the separate components may be shared among severalnetwork nodes. For example, a single RNC may control multiple NodeB's.In such a scenario, each unique NodeB and RNC pair, may in someinstances be considered a single separate network node. In someembodiments, network node 1160 may be configured to support multipleradio access technologies (RATs). In such embodiments, some componentsmay be duplicated (e.g., separate device readable medium 1180 for thedifferent RATs) and some components may be reused (e.g., the sameantenna 1162 may be shared by the RATs). Network node 1160 may alsoinclude multiple sets of the various illustrated components fordifferent wireless technologies integrated into network node 1160, suchas, for example, GSM, WCDMA, LTE, NR, WiFi, or Bluetooth wirelesstechnologies. These wireless technologies may be integrated into thesame or different chip or set of chips and other components withinnetwork node 1160.

Processing circuitry 1170 is configured to perform any determining,calculating, or similar operations (e.g., certain obtaining operations)described herein as being provided by a network node. These operationsperformed by processing circuitry 1170 may include processinginformation obtained by processing circuitry 1170 by, for example,converting the obtained information into other information, comparingthe obtained information or converted information to information storedin the network node, and/or performing one or more operations based onthe obtained information or converted information, and as a result ofsaid processing making a determination.

Processing circuitry 1170 may comprise a combination of one or more of amicroprocessor, controller, microcontroller, central processing unit,digital signal processor, application-specific integrated circuit, fieldprogrammable gate array, or any other suitable computing device,resource, or combination of hardware, software and/or encoded logicoperable to provide, either alone or in conjunction with other networknode 1160 components, such as device readable medium 1180, network node1160 functionality. For example, processing circuitry 1170 may executeinstructions stored in device readable medium 1180 or in memory withinprocessing circuitry 1170. Such functionality may include providing anyof the various wireless features, functions, or benefits discussedherein. In some embodiments, processing circuitry 1170 may include asystem on a chip (SOC).

In some embodiments, processing circuitry 1170 may include one or moreof radio frequency (RF) transceiver circuitry 1172 and basebandprocessing circuitry 1174. In some embodiments, radio frequency (RF)transceiver circuitry 1172 and baseband processing circuitry 1174 may beon separate chips (or sets of chips), boards, or units, such as radiounits and digital units. In alternative embodiments, part or all of RFtransceiver circuitry 1172 and baseband processing circuitry 1174 may beon the same chip or set of chips, boards, or units.

In certain embodiments, some or all of the functionality describedherein as being provided by a network node, base station, eNB or othersuch network device may be performed by processing circuitry 1170executing instructions stored on device readable medium 1180 or memorywithin processing circuitry 1170. In alternative embodiments, some orall of the functionality may be provided by processing circuitry 1170without executing instructions stored on a separate or discrete devicereadable medium, such as in a hard-wired manner. In any of thoseembodiments, whether executing instructions stored on a device readablestorage medium or not, processing circuitry 1170 can be configured toperform the described functionality. The benefits provided by suchfunctionality are not limited to processing circuitry 1170 alone or toother components of network node 1160, but are enjoyed by network node1160 as a whole, and/or by end users and the wireless network generally.

Device readable medium 1180 may comprise any form of volatile ornon-volatile computer readable memory including, without limitation,persistent storage, solid-state memory, remotely mounted memory,magnetic media, optical media, random access memory (RAM), read-onlymemory (ROM), mass storage media (for example, a hard disk), removablestorage media (for example, a flash drive, a Compact Disk (CD) or aDigital Video Disk (DVD)), and/or any other volatile or non-volatile,non-transitory device readable and/or computer-executable memory devicesthat store information, data, and/or instructions that may be used byprocessing circuitry 1170. Device readable medium 1180 may store anysuitable instructions, data or information, including a computerprogram, software, an application including one or more of logic, rules,code, tables, etc. and/or other instructions capable of being executedby processing circuitry 1170 and, utilized by network node 1160. Devicereadable medium 1180 may be used to store any calculations made byprocessing circuitry 1170 and/or any data received via interface 1190.In some embodiments, processing circuitry 1170 and device readablemedium 1180 may be considered to be integrated.

Interface 1190 is used in the wired or wireless communication ofsignaling and/or data between network node 1160, network 1106, and/orWDs 1110. As illustrated, interface 1190 comprises port(s)/terminal(s)1194 to send and receive data, for example to and from network 1106 overa wired connection. Interface 1190 also includes radio front endcircuitry 1192 that may be coupled to, or in certain embodiments a partof, antenna 1162. Radio front end circuitry 1192 comprises filters 1198and amplifiers 1196. Radio front end circuitry 1192 may be connected toantenna 1162 and processing circuitry 1170. Radio front end circuitrymay be configured to condition signals communicated between antenna 1162and processing circuitry 1170. Radio front end circuitry 1192 mayreceive digital data that is to be sent out to other network nodes orWDs via a wireless connection. Radio front end circuitry 1192 mayconvert the digital data into a radio signal having the appropriatechannel and bandwidth parameters using a combination of filters 1198and/or amplifiers 1196. The radio signal may then be transmitted viaantenna 1162. Similarly, when receiving data, antenna 1162 may collectradio signals which are then converted into digital data by radio frontend circuitry 1192. The digital data may be passed to processingcircuitry 1170. In other embodiments, the interface may comprisedifferent components and/or different combinations of components.

In certain alternative embodiments, network node 1160 may not includeseparate radio front end circuitry 1192, instead, processing circuitry1170 may comprise radio front end circuitry and may be connected toantenna 1162 without separate radio front end circuitry 1192. Similarly,in some embodiments, all or some of RF transceiver circuitry 1172 may beconsidered a part of interface 1190. In still other embodiments,interface 1190 may include one or more ports or terminals 1194, radiofront end circuitry 1192, and RF transceiver circuitry 1172, as part ofa radio unit (not shown), and interface 1190 may communicate withbaseband processing circuitry 1174, which is part of a digital unit (notshown).

Antenna 1162 may include one or more antennas, or antenna arrays,configured to send and/or receive wireless signals. Antenna 1162 may becoupled to radio front end circuitry 1190 and may be any type of antennacapable of transmitting and receiving data and/or signals wirelessly. Insome embodiments, antenna 1162 may comprise one or moreomni-directional, sector or panel antennas operable to transmit/receiveradio signals between, for example, 2 GHz and 66 GHz. Anomni-directional antenna may be used to transmit/receive radio signalsin any direction, a sector antenna may be used to transmit/receive radiosignals from devices within a particular area, and a panel antenna maybe a line of sight antenna used to transmit/receive radio signals in arelatively straight line. In some instances, the use of more than oneantenna may be referred to as MIMO. In certain embodiments, antenna 1162may be separate from network node 1160 and may be connectable to networknode 1160 through an interface or port.

Antenna 1162, interface 1190, and/or processing circuitry 1170 may beconfigured to perform any receiving operations and/or certain obtainingoperations described herein as being performed by a network node. Anyinformation, data and/or signals may be received from a wireless device,another network node and/or any other network equipment. Similarly,antenna 1162, interface 1190, and/or processing circuitry 1170 may beconfigured to perform any transmitting operations described herein asbeing performed by a network node. Any information, data and/or signalsmay be transmitted to a wireless device, another network node and/or anyother network equipment.

Power circuitry 1187 may comprise, or be coupled to, power managementcircuitry and is configured to supply the components of network node1160 with power for performing the functionality described herein. Powercircuitry 1187 may receive power from power source 1186. Power source1186 and/or power circuitry 1187 may be configured to provide power tothe various components of network node 1160 in a form suitable for therespective components (e.g., at a voltage and current level needed foreach respective component). Power source 1186 may either be included in,or external to, power circuitry 1187 and/or network node 1160. Forexample, network node 1160 may be connectable to an external powersource (e.g., an electricity outlet) via an input circuitry or interfacesuch as an electrical cable, whereby the external power source suppliespower to power circuitry 1187. As a further example, power source 1186may comprise a source of power in the form of a battery or battery packwhich is connected to, or integrated in, power circuitry 1187. Thebattery may provide backup power should the external power source fail.Other types of power sources, such as photovoltaic devices, may also beused.

Alternative embodiments of network node 1160 may include additionalcomponents beyond those shown in FIG. 21 that may be responsible forproviding certain aspects of the network node's functionality, includingany of the functionality described herein and/or any functionalitynecessary to support the subject matter described herein. For example,network node 1160 may include user interface equipment to allow input ofinformation into network node 1160 and to allow output of informationfrom network node 1160. This may allow a user to perform diagnostic,maintenance, repair, and other administrative functions for network node1160.

As used herein, wireless device (WD) refers to a device capable,configured, arranged and/or operable to communicate wirelessly withnetwork nodes and/or other wireless devices. Unless otherwise noted, theterm WD may be used interchangeably herein with user equipment (UE).Communicating wirelessly may involve transmitting and/or receivingwireless signals using electromagnetic waves, radio waves, infraredwaves, and/or other types of signals suitable for conveying informationthrough air. In some embodiments, a WD may be configured to transmitand/or receive information without direct human interaction. Forinstance, a WD may be designed to transmit information to a network on apredetermined schedule, when triggered by an internal or external event,or in response to requests from the network. Examples of a WD include,but are not limited to, a smart phone, a mobile phone, a cell phone, avoice over IP (VoIP) phone, a wireless local loop phone, a desktopcomputer, a personal digital assistant (PDA), a wireless cameras, agaming console or device, a music storage device, a playback appliance,a wearable terminal device, a wireless endpoint, a mobile station, atablet, a laptop, a laptop-embedded equipment (LEE), a laptop-mountedequipment (LME), a smart device, a wireless customer-premise equipment(CPE). a vehicle-mounted wireless terminal device, etc. A WD may supportdevice-to-device (D2D) communication, for example by implementing a 3GPPstandard for sidelink communication, vehicle-to-vehicle (V2V),vehicle-to-infrastructure (V2I), vehicle-to-everything (V2X) and may inthis case be referred to as a D2D communication device. As yet anotherspecific example, in an Internet of Things (IoT) scenario, a WD mayrepresent a machine or other device that performs monitoring and/ormeasurements, and transmits the results of such monitoring and/ormeasurements to another WD and/or a network node. The WD may in thiscase be a machine-to-machine (M2M) device, which may in a 3GPP contextbe referred to as an MTC device. As one particular example, the WD maybe a UE implementing the 3GPP narrow band internet of things (NB-IoT)standard. Particular examples of such machines or devices are sensors,metering devices such as power meters, industrial machinery, or home orpersonal appliances (e.g. refrigerators, televisions, etc.) personalwearables (e.g., watches, fitness trackers, etc.). In other scenarios, aWD may represent a vehicle or other equipment that is capable ofmonitoring and/or reporting on its operational status or other functionsassociated with its operation. A WD as described above may represent theendpoint of a wireless connection, in which case the device may bereferred to as a wireless terminal. Furthermore, a WD as described abovemay be mobile, in which case it may also be referred to as a mobiledevice or a mobile terminal.

As illustrated, wireless device 1110 includes antenna 1111, interface1114, processing circuitry 1120, device readable medium 1130, userinterface equipment 1132, auxiliary equipment 1134, power source 1136and power circuitry 1137. WD 1110 may include multiple sets of one ormore of the illustrated components for different wireless technologiessupported by WD 1110, such as, for example, GSM, WCDMA, LTE, NR, WiFi,WiMAX, NB-IoT, or Bluetooth wireless technologies, just to mention afew. These wireless technologies may be integrated into the same ordifferent chips or set of chips as other components within WD 1110.

Antenna 1111 may include one or more antennas or antenna arrays,configured to send and/or receive wireless signals, and is connected tointerface 1114. In certain alternative embodiments, antenna 1111 may beseparate from WD 1110 and be connectable to WD 1110 through an interfaceor port. Antenna 1111, interface 1114, and/or processing circuitry 1120may be configured to perform any receiving or transmitting operationsdescribed herein as being performed by a WD. Any information, dataand/or signals may be received from a network node and/or another WD. Insome embodiments, radio front end circuitry and/or antenna 1111 may beconsidered an interface.

As illustrated, interface 1114 comprises radio front end circuitry 1112and antenna 1111. Radio front end circuitry 1112 comprise one or morefilters 1118 and amplifiers 1116. Radio front end circuitry 1114 isconnected to antenna 1111 and processing circuitry 1120, and isconfigured to condition signals communicated between antenna 1111 andprocessing circuitry 1120. Radio front end circuitry 1112 may be coupledto or a part of antenna 1111. In some embodiments, WD 1110 may notinclude separate radio front end circuitry 1112; rather, processingcircuitry 1120 may comprise radio front end circuitry and may beconnected to antenna 1111. Similarly, in some embodiments, some or allof RF transceiver circuitry 1122 may be considered a part of interface1114. Radio front end circuitry 1112 may receive digital data that is tobe sent out to other network nodes or WDs via a wireless connection.Radio front end circuitry 1112 may convert the digital data into a radiosignal having the appropriate channel and bandwidth parameters using acombination of filters 1118 and/or amplifiers 1116. The radio signal maythen be transmitted via antenna 1111. Similarly, when receiving data,antenna 1111 may collect radio signals which are then converted intodigital data by radio front end circuitry 1112. The digital data may bepassed to processing circuitry 1120. In other embodiments, the interfacemay comprise different components and/or different combinations ofcomponents.

Processing circuitry 1120 may comprise a combination of one or more of amicroprocessor, controller, microcontroller, central processing unit,digital signal processor, application-specific integrated circuit, fieldprogrammable gate array, or any other suitable computing device,resource, or combination of hardware, software, and/or encoded logicoperable to provide, either alone or in conjunction with other WD 1110components, such as device readable medium 1130, WD 1110 functionality.Such functionality may include providing any of the various wirelessfeatures or benefits discussed herein. For example, processing circuitry1120 may execute instructions stored in device readable medium 1130 orin memory within processing circuitry 1120 to provide the functionalitydisclosed herein.

As illustrated, processing circuitry 1120 includes one or more of RFtransceiver circuitry 1122, baseband processing circuitry 1124, andapplication processing circuitry 1126. In other embodiments, theprocessing circuitry may comprise different components and/or differentcombinations of components. In certain embodiments processing circuitry1120 of WD 1110 may comprise a SOC. In some embodiments, RF transceivercircuitry 1122, baseband processing circuitry 1124, and applicationprocessing circuitry 1126 may be on separate chips or sets of chips. Inalternative embodiments, part or all of baseband processing circuitry1124 and application processing circuitry 1126 may be combined into onechip or set of chips, and RF transceiver circuitry 1122 may be on aseparate chip or set of chips. In still alternative embodiments, part orall of RF transceiver circuitry 1122 and baseband processing circuitry1124 may be on the same chip or set of chips, and application processingcircuitry 1126 may be on a separate chip or set of chips. In yet otheralternative embodiments, part or all of RF transceiver circuitry 1122,baseband processing circuitry 1124, and application processing circuitry1126 may be combined in the same chip or set of chips. In someembodiments, RF transceiver circuitry 1122 may be a part of interface1114. RF transceiver circuitry 1122 may condition RF signals forprocessing circuitry 1120.

In certain embodiments, some or all of the functionality describedherein as being performed by a WD may be provided by processingcircuitry 1120 executing instructions stored on device readable medium1130, which in certain embodiments may be a computer-readable storagemedium. In alternative embodiments, some or all of the functionality maybe provided by processing circuitry 1120 without executing instructionsstored on a separate or discrete device readable storage medium, such asin a hard-wired manner. In any of those particular embodiments, whetherexecuting instructions stored on a device readable storage medium ornot, processing circuitry 1120 can be configured to perform thedescribed functionality. The benefits provided by such functionality arenot limited to processing circuitry 1120 alone or to other components ofWD 1110, but are enjoyed by WD 1110 as a whole, and/or by end users andthe wireless network generally.

Processing circuitry 1120 may be configured to perform any determining,calculating, or similar operations (e.g., certain obtaining operations)described herein as being performed by a WD. These operations, asperformed by processing circuitry 1120, may include processinginformation obtained by processing circuitry 1120 by, for example,converting the obtained information into other information, comparingthe obtained information or converted information to information storedby WD 1110, and/or performing one or more operations based on theobtained information or converted information, and as a result of saidprocessing making a determination.

Device readable medium 1130 may be operable to store a computer program,software, an application including one or more of logic, rules, code,tables, etc. and/or other instructions capable of being executed byprocessing circuitry 1120. Device readable medium 1130 may includecomputer memory (e.g., Random Access Memory (RAM) or Read Only Memory(ROM)), mass storage media (e.g., a hard disk), removable storage media(e.g., a Compact Disk (CD) or a Digital Video Disk (DVD)), and/or anyother volatile or non-volatile, non-transitory device readable and/orcomputer executable memory devices that store information, data, and/orinstructions that may be used by processing circuitry 1120. In someembodiments, processing circuitry 1120 and device readable medium 1130may be considered to be integrated.

User interface equipment 1132 may provide components that allow for ahuman user to interact with WD 1110. Such interaction may be of manyforms, such as visual, audial, tactile, etc. User interface equipment1132 may be operable to produce output to the user and to allow the userto provide input to WD 1110. The type of interaction may vary dependingon the type of user interface equipment 1132 installed in WD 1110. Forexample, if WD 1110 is a smart phone, the interaction may be via a touchscreen; if WD 1110 is a smart meter, the interaction may be through ascreen that provides usage (e.g., the number of gallons used) or aspeaker that provides an audible alert (e.g., if smoke is detected).User interface equipment 1132 may include input interfaces, devices andcircuits, and output interfaces, devices and circuits. User interfaceequipment 1132 is configured to allow input of information into WD 1110,and is connected to processing circuitry 1120 to allow processingcircuitry 1120 to process the input information. User interfaceequipment 1132 may include, for example, a microphone, a proximity orother sensor, keys/buttons, a touch display, one or more cameras, a USBport, or other input circuitry. User interface equipment 1132 is alsoconfigured to allow output of information from WD 1110, and to allowprocessing circuitry 1120 to output information from WD 1110. Userinterface equipment 1132 may include, for example, a speaker, a display,vibrating circuitry, a USB port, a headphone interface, or other outputcircuitry. Using one or more input and output interfaces, devices, andcircuits, of user interface equipment 1132, WD 1110 may communicate withend users and/or the wireless network, and allow them to benefit fromthe functionality described herein.

Auxiliary equipment 1134 is operable to provide more specificfunctionality which may not be generally performed by WDs. This maycomprise specialized sensors for doing measurements for variouspurposes, interfaces for additional types of communication such as wiredcommunications etc. The inclusion and type of components of auxiliaryequipment 1134 may vary depending on the embodiment and/or scenario.

Power source 1136 may, in some embodiments, be in the form of a batteryor battery pack. Other types of power sources, such as an external powersource (e.g., an electricity outlet), photovoltaic devices or powercells, may also be used. WD 1110 may further comprise power circuitry1137 for delivering power from power source 1136 to the various parts ofWD 1110 which need power from power source 1136 to carry out anyfunctionality described or indicated herein. Power circuitry 1137 may incertain embodiments comprise power management circuitry. Power circuitry1137 may additionally or alternatively be operable to receive power froman external power source; in which case WD 1110 may be connectable tothe external power source (such as an electricity outlet) via inputcircuitry or an interface such as an electrical power cable. Powercircuitry 1137 may also in certain embodiments be operable to deliverpower from an external power source to power source 1136. This may be,for example, for the charging of power source 1136. Power circuitry 1137may perform any formatting, converting, or other modification to thepower from power source 1136 to make the power suitable for therespective components of WD 1110 to which power is supplied.

FIG. 22 illustrates one embodiment of a UE in accordance with variousaspects described herein. As used herein, a user equipment or UE may notnecessarily have a user in the sense of a human user who owns and/oroperates the relevant device. Instead, a UE may represent a device thatis intended for sale to, or operation by, a human user but which maynot, or which may not initially, be associated with a specific humanuser (e.g., a smart sprinkler controller). Alternatively, a UE mayrepresent a device that is not intended for sale to, or operation by, anend user but which may be associated with or operated for the benefit ofa user (e.g., a smart power meter). UE 12200 may be any UE identified bythe 3rd Generation Partnership Project (3GPP), including a NB-IoT UE, amachine type communication (MTC) UE, and/or an enhanced MTC (eMTC) UE.UE 1200, as illustrated in FIG. 22, is one example of a WD configuredfor communication in accordance with one or more communication standardspromulgated by the 3rd Generation Partnership Project (3GPP), such as3GPP's GSM, UMTS, LTE, and/or 5G standards. As mentioned previously, theterm WD and UE may be used interchangeable. Accordingly, although FIG.22 is a UE, the components discussed herein are equally applicable to aWD, and vice-versa.

In FIG. 22, UE 1200 includes processing circuitry 1201 that isoperatively coupled to input/output interface 1205, radio frequency (RF)interface 1209, network connection interface 1211, memory 1215 includingrandom access memory (RAM) 1217, read-only memory (ROM) 1219, andstorage medium 1221 or the like, communication subsystem 1231, powersource 1233, and/or any other component, or any combination thereof.Storage medium 1221 includes operating system 1223, application program1225, and data 1227. In other embodiments, storage medium 1221 mayinclude other similar types of information. Certain UEs may utilize allof the components shown in FIG. 22, or only a subset of the components.The level of integration between the components may vary from one UE toanother UE. Further, certain UEs may contain multiple instances of acomponent, such as multiple processors, memories, transceivers,transmitters, receivers, etc.

In FIG. 22, processing circuitry 1201 may be configured to processcomputer instructions and data. Processing circuitry 1201 may beconfigured to implement any sequential state machine operative toexecute machine instructions stored as machine-readable computerprograms in the memory, such as one or more hardware-implemented statemachines (e.g., in discrete logic, FPGA, ASIC, etc.); programmable logictogether with appropriate firmware; one or more stored program,general-purpose processors, such as a microprocessor or Digital SignalProcessor (DSP), together with appropriate software; or any combinationof the above. For example, the processing circuitry 1201 may include twocentral processing units (CPUs). Data may be information in a formsuitable for use by a computer.

In the depicted embodiment, input/output interface 1205 may beconfigured to provide a communication interface to an input device,output device, or input and output device. UE 1200 may be configured touse an output device via input/output interface 1205. An output devicemay use the same type of interface port as an input device. For example,a USB port may be used to provide input to and output from UE 1200. Theoutput device may be a speaker, a sound card, a video card, a display, amonitor, a printer, an actuator, an emitter, a smartcard, another outputdevice, or any combination thereof. UE 1200 may be configured to use aninput device via input/output interface 1205 to allow a user to captureinformation into UE 1200. The input device may include a touch-sensitiveor presence-sensitive display, a camera (e.g., a digital camera, adigital video camera, a web camera, etc.), a microphone, a sensor, amouse, a trackball, a directional pad, a trackpad, a scroll wheel, asmartcard, and the like. The presence-sensitive display may include acapacitive or resistive touch sensor to sense input from a user. Asensor may be, for instance, an accelerometer, a gyroscope, a tiltsensor, a force sensor, a magnetometer, an optical sensor, a proximitysensor, another like sensor, or any combination thereof. For example,the input device may be an accelerometer, a magnetometer, a digitalcamera, a microphone, and an optical sensor.

In FIG. 22, RF interface 1209 may be configured to provide acommunication interface to RF components such as a transmitter, areceiver, and an antenna. Network connection interface 1211 may beconfigured to provide a communication interface to network 1243 a.Network 1243 a may encompass wired and/or wireless networks such as alocal-area network (LAN), a wide-area network (WAN), a computer network,a wireless network, a telecommunications network, another like networkor any combination thereof. For example, network 1243 a may comprise aWi-Fi network. Network connection interface 1211 may be configured toinclude a receiver and a transmitter interface used to communicate withone or more other devices over a communication network according to oneor more communication protocols, such as Ethernet, TCP/IP, SONET, ATM,or the like. Network connection interface 1211 may implement receiverand transmitter functionality appropriate to the communication networklinks (e.g., optical, electrical, and the like). The transmitter andreceiver functions may share circuit components, software or firmware,or alternatively may be implemented separately.

RAM 1217 may be configured to interface via bus 1202 to processingcircuitry 1201 to provide storage or caching of data or computerinstructions during the execution of software programs such as theoperating system, application programs, and device drivers. ROM 1219 maybe configured to provide computer instructions or data to processingcircuitry 1201. For example, ROM 1219 may be configured to storeinvariant low-level system code or data for basic system functions suchas basic input and output (I/O), startup, or reception of keystrokesfrom a keyboard that are stored in a non-volatile memory. Storage medium1221 may be configured to include memory such as RAM, ROM, programmableread-only memory (PROM), erasable programmable read-only memory (EPROM),electrically erasable programmable read-only memory (EEPROM), magneticdisks, optical disks, floppy disks, hard disks, removable cartridges, orflash drives. In one example, storage medium 1221 may be configured toinclude operating system 1223, application program 1225 such as a webbrowser application, a widget or gadget engine or another application,and data file 1227. Storage medium 1221 may store, for use by UE 1200,any of a variety of various operating systems or combinations ofoperating systems.

Storage medium 1221 may be configured to include a number of physicaldrive units, such as redundant array of independent disks (RAID), floppydisk drive, flash memory, USB flash drive, external hard disk drive,thumb drive, pen drive, key drive, high-density digital versatile disc(HD-DVD) optical disc drive, internal hard disk drive, Blu-Ray opticaldisc drive, holographic digital data storage (HDDS) optical disc drive,external mini-dual in-line memory module (DIMM), synchronous dynamicrandom access memory (SDRAM), external micro-DIMM SDRAM, smartcardmemory such as a subscriber identity module or a removable user identity(SIM/RUIM) module, other memory, or any combination thereof. Storagemedium 1221 may allow UE 1200 to access computer-executableinstructions, application programs or the like, stored on transitory ornon-transitory memory media, to off-load data, or to upload data. Anarticle of manufacture, such as one utilizing a communication system maybe tangibly embodied in storage medium 1221, which may comprise a devicereadable medium.

In FIG. 22, processing circuitry 1201 may be configured to communicatewith network 1243 b using communication subsystem 1231. Network 1243 aand network 1243 b may be the same network or networks or differentnetwork or networks. Communication subsystem 1231 may be configured toinclude one or more transceivers used to communicate with network 1243b. For example, communication subsystem 1231 may be configured toinclude one or more transceivers used to communicate with one or moreremote transceivers of another device capable of wireless communicationsuch as another WD, UE, or base station of a radio access network (RAN)according to one or more communication protocols, such as IEEE 802.12,CDMA, WCDMA, GSM, LTE, UTRAN, WiMax, or the like. Each transceiver mayinclude transmitter 1233 and/or receiver 1235 to implement transmitteror receiver functionality, respectively, appropriate to the RAN links(e.g., frequency allocations and the like). Further, transmitter 1233and receiver 1235 of each transceiver may share circuit components,software or firmware, or alternatively may be implemented separately.

In the illustrated embodiment, the communication functions ofcommunication subsystem 1231 may include data communication, voicecommunication, multimedia communication, short-range communications suchas Bluetooth, near-field communication, location-based communicationsuch as the use of the global positioning system (GPS) to determine alocation, another like communication function, or any combinationthereof. For example, communication subsystem 1231 may include cellularcommunication, Wi-Fi communication, Bluetooth communication, and GPScommunication. Network 1243 b may encompass wired and/or wirelessnetworks such as a local-area network (LAN), a wide-area network (WAN),a computer network, a wireless network, a telecommunications network,another like network or any combination thereof. For example, network1243 b may be a cellular network, a Wi-Fi network, and/or a near-fieldnetwork. Power source 1213 may be configured to provide alternatingcurrent (AC) or direct current (DC) power to components of UE 1200.

The features, benefits and/or functions described herein may beimplemented in one of the components of UE 1200 or partitioned acrossmultiple components of UE 1200. Further, the features, benefits, and/orfunctions described herein may be implemented in any combination ofhardware, software or firmware. In one example, communication subsystem1231 may be configured to include any of the components describedherein. Further, processing circuitry 1201 may be configured tocommunicate with any of such components over bus 1202. In anotherexample, any of such components may be represented by programinstructions stored in memory that when executed by processing circuitry1201 perform the corresponding functions described herein. In anotherexample, the functionality of any of such components may be partitionedbetween processing circuitry 1201 and communication subsystem 1231. Inanother example, the non-computationally intensive functions of any ofsuch components may be implemented in software or firmware and thecomputationally intensive functions may be implemented in hardware.

FIG. 23 is a schematic block diagram illustrating a virtualizationenvironment 1300 in which functions implemented by some embodiments maybe virtualized. In the present context, virtualizing means creatingvirtual versions of apparatuses or devices which may includevirtualizing hardware platforms, storage devices and networkingresources. As used herein, virtualization can be applied to a node(e.g., a virtualized base station or a virtualized radio access node) orto a device (e.g., a UE, a wireless device or any other type ofcommunication device) or components thereof and relates to animplementation in which at least a portion of the functionality isimplemented as one or more virtual components (e.g., via one or moreapplications, components, functions, virtual machines or containersexecuting on one or more physical processing nodes in one or morenetworks).

In some embodiments, some or all of the functions described herein maybe implemented as virtual components executed by one or more virtualmachines implemented in one or more virtual environments 1300 hosted byone or more of hardware nodes 1330. Further, in embodiments in which thevirtual node is not a radio access node or does not require radioconnectivity (e.g., a core network node), then the network node may beentirely virtualized.

The functions may be implemented by one or more applications 1320 (whichmay alternatively be called software instances, virtual appliances,network functions, virtual nodes, virtual network functions, etc.)operative to implement some of the features, functions, and/or benefitsof some of the embodiments disclosed herein. Applications 1320 are runin virtualization environment 1300 which provides hardware 1330comprising processing circuitry 1360 and memory 1390. Memory 1390contains instructions 1395 executable by processing circuitry 1360whereby application 1320 is operative to provide one or more of thefeatures, benefits, and/or functions disclosed herein.

Virtualization environment 1300, comprises general-purpose orspecial-purpose network hardware devices 1330 comprising a set of one ormore processors or processing circuitry 1360, which may be commercialoff-the-shelf (COTS) processors, dedicated Application SpecificIntegrated Circuits (ASICs), or any other type of processing circuitryincluding digital or analog hardware components or special purposeprocessors. Each hardware device may comprise memory 1390-1 which may benon-persistent memory for temporarily storing instructions 1395 orsoftware executed by processing circuitry 1360. Each hardware device maycomprise one or more network interface controllers (NICs) 1370, alsoknown as network interface cards, which include physical networkinterface 1380. Each hardware device may also include non-transitory,persistent, machine-readable storage media 1390-2 having stored thereinsoftware 1395 and/or instructions executable by processing circuitry1360. Software 1395 may include any type of software including softwarefor instantiating one or more virtualization layers 1350 (also referredto as hypervisors), software to execute virtual machines 1340 as well assoftware allowing it to execute functions, features and/or benefitsdescribed in relation with some embodiments described herein.

Virtual machines 1340, comprise virtual processing, virtual memory,virtual networking or interface and virtual storage, and may be run by acorresponding virtualization layer 1350 or hypervisor. Differentembodiments of the instance of virtual appliance 1320 may be implementedon one or more of virtual machines 1340, and the implementations may bemade in different ways.

During operation, processing circuitry 1360 executes software 1395 toinstantiate the hypervisor or virtualization layer 1350, which maysometimes be referred to as a virtual machine monitor (VMM).Virtualization layer 1350 may present a virtual operating platform thatappears like networking hardware to virtual machine 1340.

As shown in FIG. 23, hardware 1330 may be a standalone network node withgeneric or specific components. Hardware 1330 may comprise antenna 13225and may implement some functions via virtualization. Alternatively,hardware 1330 may be part of a larger cluster of hardware (e.g. such asin a data center or customer premise equipment (CPE)) where manyhardware nodes work together and are managed via management andorchestration (MANO) 13100, which, among others, oversees lifecyclemanagement of applications 1320.

Virtualization of the hardware is in some contexts referred to asnetwork function virtualization (NFV). NFV may be used to consolidatemany network equipment types onto industry standard high volume serverhardware, physical switches, and physical storage, which can be locatedin data centers, and customer premise equipment.

In the context of NFV, virtual machine 1340 may be a softwareimplementation of a physical machine that runs programs as if they wereexecuting on a physical, non-virtualized machine. Each of virtualmachines 1340, and that part of hardware 1330 that executes that virtualmachine, be it hardware dedicated to that virtual machine and/orhardware shared by that virtual machine with others of the virtualmachines 1340, forms a separate virtual network elements (VNE).

Still in the context of NFV, Virtual Network Function (VNF) isresponsible for handling specific network functions that run in one ormore virtual machines 1340 on top of hardware networking infrastructure1330 and corresponds to application 1320 in FIG. 23.

In some embodiments, one or more radio units 13200 that each include oneor more transmitters 13220 and one or more receivers 13210 may becoupled to one or more antennas 13225. Radio units 13200 may communicatedirectly with hardware nodes 1330 via one or more appropriate networkinterfaces and may be used in combination with the virtual components toprovide a virtual node with radio capabilities, such as a radio accessnode or a base station.

In some embodiments, some signalling can be effected with the use ofcontrol system 13230 which may alternatively be used for communicationbetween the hardware nodes 1330 and radio units 13200.

FIG. 24 illustrates a telecommunication network connected via anintermediate network to a host computer in accordance with someembodiments. In particular, with reference to FIG. 24, in accordancewith an embodiment, a communication system includes telecommunicationnetwork 1410, such as a 3GPP-type cellular network, which comprisesaccess network 1411, such as a radio access network, and core network1414. Access network 1411 comprises a plurality of base stations 1412 a,1412 b, 1412 c, such as NBs, eNBs, gNBs or other types of wirelessaccess points, each defining a corresponding coverage area 1413 a, 1413b, 1413 c. Each base station 1412 a, 1412 b, 1412 c is connectable tocore network 1414 over a wired or wireless connection 1415. A first UE1491 located in coverage area 1413 c is configured to wirelessly connectto, or be paged by, the corresponding base station 1412 c. A second UE1492 in coverage area 1413 a is wirelessly connectable to thecorresponding base station 1412 a. While a plurality of UEs 1491, 1492are illustrated in this example, the disclosed embodiments are equallyapplicable to a situation where a sole UE is in the coverage area orwhere a sole UE is connecting to the corresponding base station 1412.

Telecommunication network 1410 is itself connected to host computer1430, which may be embodied in the hardware and/or software of astandalone server, a cloud-implemented server, a distributed server oras processing resources in a server farm. Host computer 1430 may beunder the ownership or control of a service provider, or may be operatedby the service provider or on behalf of the service provider.Connections 1421 and 1422 between telecommunication network 1410 andhost computer 1430 may extend directly from core network 1414 to hostcomputer 1430 or may go via an optional intermediate network 1420.Intermediate network 1420 may be one of, or a combination of more thanone of, a public, private or hosted network; intermediate network 1420,if any, may be a backbone network or the Internet; in particular,intermediate network 1420 may comprise two or more sub-networks (notshown).

The communication system of FIG. 24 as a whole enables connectivitybetween the connected UEs 1491, 1492 and host computer 1430. Theconnectivity may be described as an over-the-top (OTT) connection 1450.Host computer 1430 and the connected UEs 1491, 1492 are configured tocommunicate data and/or signaling via OTT connection 1450, using accessnetwork 1411, core network 1414, any intermediate network 1420 andpossible further infrastructure (not shown) as intermediaries. OTTconnection 1450 may be transparent in the sense that the participatingcommunication devices through which OTT connection 1450 passes areunaware of routing of uplink and downlink communications. For example,base station 1412 may not or need not be informed about the past routingof an incoming downlink communication with data originating from hostcomputer 1430 to be forwarded (e.g., handed over) to a connected UE1491. Similarly, base station 1412 need not be aware of the futurerouting of an outgoing uplink communication originating from the UE 1491towards the host computer 1430.

Example implementations, in accordance with an embodiment, of the UE,base station and host computer discussed in the preceding paragraphswill now be described with reference to FIG. 25. FIG. 25 illustrateshost computer communicating via a base station with a user equipmentover a partially wireless connection in accordance with some embodimentsIn communication system 1500, host computer 1510 comprises hardware 1515including communication interface 1516 configured to set up and maintaina wired or wireless connection with an interface of a differentcommunication device of communication system 1500. Host computer 1510further comprises processing circuitry 1518, which may have storageand/or processing capabilities. In particular, processing circuitry 1518may comprise one or more programmable processors, application-specificintegrated circuits, field programmable gate arrays or combinations ofthese (not shown) adapted to execute instructions. Host computer 1510further comprises software 1511, which is stored in or accessible byhost computer 1510 and executable by processing circuitry 1518. Software1511 includes host application 1512. Host application 1512 may beoperable to provide a service to a remote user, such as UE 1530connecting via OTT connection 1550 terminating at UE 1530 and hostcomputer 1510. In providing the service to the remote user, hostapplication 1512 may provide user data which is transmitted using OTTconnection 1550.

Communication system 1500 further includes base station 1520 provided ina telecommunication system and comprising hardware 1525 enabling it tocommunicate with host computer 1510 and with UE 1530. Hardware 1525 mayinclude communication interface 1526 for setting up and maintaining awired or wireless connection with an interface of a differentcommunication device of communication system 1500, as well as radiointerface 1527 for setting up and maintaining at least wirelessconnection 1570 with UE 1530 located in a coverage area (not shown inFIG. 25) served by base station 1520. Communication interface 1526 maybe configured to facilitate connection 1560 to host computer 1510.Connection 1560 may be direct or it may pass through a core network (notshown in FIG. 25) of the telecommunication system and/or through one ormore intermediate networks outside the telecommunication system. In theembodiment shown, hardware 1525 of base station 1520 further includesprocessing circuitry 1528, which may comprise one or more programmableprocessors, application-specific integrated circuits, field programmablegate arrays or combinations of these (not shown) adapted to executeinstructions. Base station 1520 further has software 1521 storedinternally or accessible via an external connection.

Communication system 1500 further includes UE 1530 already referred to.Its hardware 1535 may include radio interface 1537 configured to set upand maintain wireless connection 1570 with a base station serving acoverage area in which UE 1530 is currently located. Hardware 1535 of UE1530 further includes processing circuitry 1538, which may comprise oneor more programmable processors, application-specific integratedcircuits, field programmable gate arrays or combinations of these (notshown) adapted to execute instructions. UE 1530 further comprisessoftware 1531, which is stored in or accessible by UE 1530 andexecutable by processing circuitry 1538. Software 1531 includes clientapplication 1532. Client application 1532 may be operable to provide aservice to a human or non-human user via UE 1530, with the support ofhost computer 1510. In host computer 1510, an executing host application1512 may communicate with the executing client application 1532 via OTTconnection 1550 terminating at UE 1530 and host computer 1510. Inproviding the service to the user, client application 1532 may receiverequest data from host application 1512 and provide user data inresponse to the request data. OTT connection 1550 may transfer both therequest data and the user data. Client application 1532 may interactwith the user to generate the user data that it provides.

It is noted that host computer 1510, base station 1520 and UE 1530illustrated in FIG. 25 may be similar or identical to host computer1430, one of base stations 1412 a, 1412 b, 1412 c and one of UEs 1491,1492 of FIG. 24, respectively. This is to say, the inner workings ofthese entities may be as shown in FIG. 25 and independently, thesurrounding network topology may be that of FIG. 24.

In FIG. 25, OTT connection 1550 has been drawn abstractly to illustratethe communication between host computer 1510 and UE 1530 via basestation 1520, without explicit reference to any intermediary devices andthe precise routing of messages via these devices. Networkinfrastructure may determine the routing, which it may be configured tohide from UE 1530 or from the service provider operating host computer1510, or both. While OTT connection 1550 is active, the networkinfrastructure may further take decisions by which it dynamicallychanges the routing (e.g., on the basis of load balancing considerationor reconfiguration of the network).

Wireless connection 1570 between UE 1530 and base station 1520 is inaccordance with the teachings of the embodiments described throughoutthis disclosure. One or more of the various embodiments improve theperformance of OTT services provided to UE 1530 using OTT connection1550, in which wireless connection 1570 forms the last segment. Moreprecisely, the teachings of these embodiments may improve the latency ofdata transmissions and thereby provide benefits such as reduced waitingtime, particularly for machine control applications.

A measurement procedure may be provided for the purpose of monitoringdata rate, latency and other factors on which the one or moreembodiments improve. There may further be an optional networkfunctionality for reconfiguring OTT connection 1550 between hostcomputer 1510 and UE 1530, in response to variations in the measurementresults. The measurement procedure and/or the network functionality forreconfiguring OTT connection 1550 may be implemented in software 1511and hardware 1515 of host computer 1510 or in software 1531 and hardware1535 of UE 1530, or both. In embodiments, sensors (not shown) may bedeployed in or in association with communication devices through whichOTT connection 1550 passes; the sensors may participate in themeasurement procedure by supplying values of the monitored quantitiesexemplified above, or supplying values of other physical quantities fromwhich software 1511, 1531 may compute or estimate the monitoredquantities. The reconfiguring of OTT connection 1550 may include messageformat, retransmission settings, preferred routing etc.; thereconfiguring need not affect base station 1520, and it may be unknownor imperceptible to base station 1520. Such procedures andfunctionalities may be known and practiced in the art. In certainembodiments, measurements may involve proprietary UE signalingfacilitating host computer 1510's measurements of throughput,propagation times, latency and the like. The measurements may beimplemented in that software 1511 and 1531 causes messages to betransmitted, in particular empty or ‘dummy’ messages, using OTTconnection 1550 while it monitors propagation times, errors etc.

FIG. 26 is a flowchart illustrating a method implemented in acommunication system, in accordance with one embodiment. Thecommunication system includes a host computer, a base station and a UEwhich may be those described with reference to FIGS. 14 and 15. Forsimplicity of the present disclosure, only drawing references to FIG. 26will be included in this section. In step 1610, the host computerprovides user data. In substep 1611 (which may be optional) of step1610, the host computer provides the user data by executing a hostapplication. In step 1620, the host computer initiates a transmissioncarrying the user data to the UE. In step 1630 (which may be optional),the base station transmits to the UE the user data which was carried inthe transmission that the host computer initiated, in accordance withthe teachings of the embodiments described throughout this disclosure.In step 1640 (which may also be optional), the UE executes a clientapplication associated with the host application executed by the hostcomputer.

FIG. 27 is a flowchart illustrating a method implemented in acommunication system, in accordance with one embodiment. Thecommunication system includes a host computer, a base station and a UEwhich may be those described with reference to FIGS. 14 and 15. Forsimplicity of the present disclosure, only drawing references to FIG. 27will be included in this section. In step 1710 of the method, the hostcomputer provides user data. In an optional substep (not shown) the hostcomputer provides the user data by executing a host application. In step1720, the host computer initiates a transmission carrying the user datato the UE. The transmission may pass via the base station, in accordancewith the teachings of the embodiments described throughout thisdisclosure. In step 1730 (which may be optional), the UE receives theuser data carried in the transmission.

FIG. 28 is a flowchart illustrating a method implemented in acommunication system, in accordance with one embodiment. Thecommunication system includes a host computer, a base station and a UEwhich may be those described with reference to FIGS. 14 and 15. Forsimplicity of the present disclosure, only drawing references to FIG. 28will be included in this section. In step 1810 (which may be optional),the UE receives input data provided by the host computer. Additionallyor alternatively, in step 1820, the UE provides user data. In substep1821 (which may be optional) of step 1820, the UE provides the user databy executing a client application. In substep 1811 (which may beoptional) of step 1810, the UE executes a client application whichprovides the user data in reaction to the received input data providedby the host computer. In providing the user data, the executed clientapplication may further consider user input received from the user.Regardless of the specific manner in which the user data was provided,the UE initiates, in substep 1830 (which may be optional), transmissionof the user data to the host computer. In step 1840 of the method, thehost computer receives the user data transmitted from the UE, inaccordance with the teachings of the embodiments described throughoutthis disclosure.

FIG. 29 is a flowchart illustrating a method implemented in acommunication system, in accordance with one embodiment. Thecommunication system includes a host computer, a base station and a UEwhich may be those described with reference to FIGS. 14 and 15. Forsimplicity of the present disclosure, only drawing references to FIG. 29will be included in this section. In step 1910 (which may be optional),in accordance with the teachings of the embodiments described throughoutthis disclosure, the base station receives user data from the UE. Instep 1920 (which may be optional), the base station initiatestransmission of the received user data to the host computer. In step1930 (which may be optional), the host computer receives the user datacarried in the transmission initiated by the base station.

Any appropriate steps, methods, features, functions, or benefitsdisclosed herein may be performed through one or more functional unitsor modules of one or more virtual apparatuses. Each virtual apparatusmay comprise a number of these functional units. These functional unitsmay be implemented via processing circuitry, which may include one ormore microprocessor or microcontrollers, as well as other digitalhardware, which may include digital signal processors (DSPs),special-purpose digital logic, and the like. The processing circuitrymay be configured to execute program code stored in memory, which mayinclude one or several types of memory such as read-only memory (ROM),random-access memory (RAM), cache memory, flash memory devices, opticalstorage devices, etc. Program code stored in memory includes programinstructions for executing one or more telecommunications and/or datacommunications protocols as well as instructions for carrying out one ormore of the techniques described herein. In some implementations, theprocessing circuitry may be used to cause the respective functional unitto perform corresponding functions according one or more embodiments ofthe present disclosure.

Generally, all terms used herein are to be interpreted according totheir ordinary meaning in the relevant technical field, unless adifferent meaning is clearly given and/or is implied from the context inwhich it is used. All references to a/an/the element, apparatus,component, means, step, etc. are to be interpreted openly as referringto at least one instance of the element, apparatus, component, means,step, etc., unless explicitly stated otherwise. The steps of any methodsdisclosed herein do not have to be performed in the exact orderdisclosed, unless a step is explicitly described as following orpreceding another step and/or where it is implicit that a step mustfollow or precede another step. Any feature of any of the embodimentsdisclosed herein may be applied to any other embodiment, whereverappropriate. Likewise, any advantage of any of the embodiments may applyto any other embodiments, and vice versa. Other objectives, features andadvantages of the enclosed embodiments will be apparent from thedescription.

The term unit may have conventional meaning in the field of electronics,electrical devices and/or electronic devices and may include, forexample, electrical and/or electronic circuitry, devices, modules,processors, memories, logic solid state and/or discrete devices,computer programs or instructions for carrying out respective tasks,procedures, computations, outputs, and/or displaying functions, and soon, as such as those that are described herein.

Some of the embodiments contemplated herein are described more fullywith reference to the accompanying drawings. Other embodiments, however,are contained within the scope of the subject matter disclosed herein.The disclosed subject matter should not be construed as limited to onlythe embodiments set forth herein; rather, these embodiments are providedby way of example to convey the scope of the subject matter to thoseskilled in the art. Other embodiments of the present disclosure areshown in Appendix A and B below.

What is claimed is:
 1. A host computer, comprising: processing circuitryconfigured to provide user data; and a communication interfaceconfigured to initiate transmission of the user data to a cellularnetwork for transmission to a user equipment (UE), wherein the cellularnetwork comprises a source Access and Mobility Management Function (AMF)in a first 5G core network, configured to support handover of a userequipment to a target AMF in the first or a second 5G core network,wherein the source AMF is configured to perform operations comprising:receiving, from a source base station in an access network of thewireless communication network, a first handover message indicating thata handover of a user equipment is needed; generating, responsive todetermining that an operator specific policy has been met, a newnon-access stratum key from a current non-access stratum key used in acurrent NAS security context shared between the user equipment and thesource Access and Mobility Management Function; sending, responsive tothe first handover message, the new non-access stratum key to a targetAccess and Mobility Management Function; receiving, from the targetAccess and Mobility Management Function, a transparent containercontaining a key change indicator flag set to a value indicating that anon-access stratum key has been changed; and sending the transparentcontainer with the key change indicator flag to the user equipment in asecond handover message.
 2. The host computer of claim 1 furthercomprising sending, to the user equipment, a key derivation parameterused to derive the new non-access stratum key.
 3. The host computer ofclaim 2 further comprising: receiving the key derivation parameter fromtarget Access and Mobility Management Function in the transparentcontainer; and sending the key derivation parameter to the userequipment in the transparent container.
 4. The host computer of claim 1wherein the first handover message is a handover required messageindicating a need for a handover of the user equipment.
 5. The hostcomputer of claim 1 wherein the non-access stratum key is a core networkkey.
 6. A non-transitory computer readable medium comprisinginstructions that, when executed by a processor in a host computer of acommunication system, cause the host computer to perform operationscomprising: providing user data; and initiating transmission of the userdata to a cellular network, via a communication interface, fortransmission to a user equipment (UE), wherein the cellular networkcomprises a source Access and Mobility Management Function (AMF) in afirst 5G core network, configured to support handover of a userequipment to a target AMF in the first or a second 5G core network,wherein the source AMF is configured to perform operations comprising:receiving, from a source base station in an access network of thewireless communication network, a first handover message indicating thata handover of a user equipment is needed; generating, responsive todetermining that an operator specific policy has been met, a newnon-access stratum key from a current non-access stratum key used in acurrent NAS security context shared between the user equipment and thesource Access and Mobility Management Function; sending, responsive tothe first handover message, the new non-access stratum key to a targetAccess and Mobility Management Function; receiving, from the targetAccess and Mobility Management Function, a transparent containercontaining a key change indicator flag set to a value indicating that anon-access stratum key has been changed; and sending the transparentcontainer with the key change indicator flag to the user equipment in asecond handover message.
 7. The non-transitory computer readable mediumof claim 6 further comprising sending, to the user equipment, a keyderivation parameter used to derive the new non-access stratum key. 8.The non-transitory computer readable medium of claim 7 furthercomprising: receiving the key derivation parameter from target Accessand Mobility Management Function in the transparent container; andsending the key derivation parameter to the user equipment in thetransparent container.
 9. The non-transitory computer readable medium ofclaim 6 wherein the first handover message is a handover requiredmessage indicating a need for a handover of the user equipment.
 10. Thenon-transitory computer readable medium of claim 6 wherein thenon-access stratum key is a core network key.
 11. A method of operatinga host computer, comprising: providing user data; and initiatingtransmission of the user data to a cellular network, via a communicationinterface, for transmission to a user equipment (UE), wherein thecellular network comprises a source Access and Mobility ManagementFunction (AMF) in a first 5G core network, configured to supporthandover of a user equipment to a target AMF in the first or a second 5Gcore network, wherein the source AMF is configured to perform operationscomprising: receiving, from a source base station in an access networkof the wireless communication network, a first handover messageindicating that a handover of a user equipment is needed; generating,responsive to determining that an operator specific policy has been met,a new non-access stratum key from a current non-access stratum key usedin a current NAS security context shared between the user equipment andthe source Access and Mobility Management Function; sending, responsiveto the first handover message, the new non-access stratum key to atarget Access and Mobility Management Function; receiving, from thetarget Access and Mobility Management Function, a transparent containercontaining a key change indicator flag set to a value indicating that anon-access stratum key has been changed; and sending the transparentcontainer with the key change indicator flag to the user equipment in asecond handover message.
 12. The method of claim 11 further comprisingsending, to the user equipment, a key derivation parameter used toderive the new non-access stratum key.
 13. The method of claim 12further comprising: receiving the key derivation parameter from targetAccess and Mobility Management Function in the transparent container;and sending the key derivation parameter to the user equipment in thetransparent container.
 14. The method of claim 11 wherein the firsthandover message is a handover required message indicating a need for ahandover of the user equipment.
 15. The method of claim 11 wherein thenon-access stratum key is a core network key.